MXPA06004786A - Process for production of essentially solvent-free small particles - Google Patents

Abstract

The present invention is concerned with the formation of small particles of an organic compound by mixing a solution of the organic compound dissolved in a water-miscible organic solvent with an aqueous medium to form a mix and simultantously homogenizing the mix while continuously removing the organic solvent to form an aqueous suspension of small particles essentially free of the organic solvent. These processes are preferably used to prepare an aqueous suspension of small particles of a poorly water-soluble, pharmaceutically active compound suitable for in vivo delivery by an administrative route such as parenteral, oral pulmonary, nasal, buccal, topical, ophthalmic, rectal, vaginal, transdermal or the like.

Description

PROCESS FOR THE PRODUCTION OF SMALL PARTICLES ESSENTIALLY FREE OF SOLVENT Cross Reference with Related Requests: This request is a continuation in part of the serial request no. 1 0 / 390,333 filed on March 7, 2003, which is a continuation in part of the serial request no. 10 / 246,802 filed e! September 1, 2002, which is a continuation in part of the serial request no. 10 / 035,821 filed on October 19, 2001, which is a continuation in part of the serial request no. 09 / 953,979 filed on September 17, 2001, which is a continuation in part of the serial request no. 09 / 874,637 filed on June 5, 2001, which claims the priority of the provisional application series no. 60/258, 160 filed on December 22, 2000. All the above-mentioned applications are incorporated herein by reference and become part of it.

Research or Development of Federal Sponsorship: Not Applicable BACKGROUND OF THE INVENTION Technical Field The present invention relates to the formation of small particles of an organic compound by mixing a solution of the organic compound dissolved in a water miscible organic solvent with an aqueous medium in order to form a mixture and homogenize the The mixture is simultaneously mixed while continuously removing the organic solvent in order to form an aqueous suspension of small particles essentially free of the organic solvent. These processes are preferably used to prepare an aqueous suspension of small particles of a pharmaceutically active compound, sparingly soluble in water, suitable for in vivo delivery via an administrative route, such as parenteral, oral, pulmonary, nasal, buccal, topical, ophthalmic, rectal, vaginal, transdermal or similar.

Prior Art There is an ever increasing number of organic compounds that are formulated for diagnostic or therapeutic effects that are sparingly soluble or insoluble in aqueous solutions. Such drugs provide obstacles to their supply through the administrative routes detailed above. Compounds that are insoluble in water can have significant benefits when formulated as a stable suspension of sub-micron particles. Accurate control of particle size is essential for the safe and effective use of these formulations. The particles must be smaller than several microns in diameter to pass safely through capillaries without causing embolisms (Alien et al., 1987, Davis and Taube, 1978, Schroeder et al., 1978, Yokel et al., 1981). . One solution to this problem is the production of small particles of the insoluble drug candidate and the creation of a microparticulate or nanoparticulate suspension. In this manner, drugs that were previously incapable of being formulated in an aqueous-based system can be made suitable for intravenous administration. What is suitable for intravenous administration includes small particle size (<7 μm), low toxicity (such as that from toxic formulation components or residual solvents) and bioavailability of the drug particles after administration. Small particle preparations of water insoluble drugs may also be suitable for oral, pulmonary, topical, ophthalmic, nasal, buccal, rectal, vaginal, transdermal or other routes of administration. The small size of the particles improves the rate of dissolution of the drug, and thus improves its bioavailability and potentially its toxicity profiles. When administered by these routes, it may be desirable to have particle sizes in the range of 5 to 100 μm, depending on the route of administration, formulation, solubility and bioavailability of the drug. For example, for oral administration, it is desirable to have a particle size of less than about 7 μm. For pulmonary administration, the particles are preferably less than about 10 μm in size.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides methods for the preparation of an aqueous suspension of small particles of an organic compound, the solubility of which is greater in a first solvent miscible in water than in a second solvent that is aqueous. The methods include (i) dissolving the organic compound in the first water-miscible solvent to form a solution; (ii) mixing the solution with the second solvent in order to form a mixture; and (ii) simultaneously homogenizing the mixture and continuously removing the first solvent from the mixture in order to form an aqueous suspension of small particles having an average effective particle size of less than about 1000 μm. The aqueous suspension is essentially free of the first solvent. In one embodiment, the mixing of the first solution with the second solvent is carried out simultaneously with the homogenization of the mixture while continuously removing the first solvent. The first solvent miscible in water can be a protic organic solvent or an aprotic organic solvent. In a preferred embodiment, the process further includes mixing one or more surface modifiers in the first solvent miscible with water or the second solvent, or both the first solvent miscible with water and the second solvent. The methods may further include sterilization of the aqueous suspension by heat sterilization or gamma irradiation. In one embodiment, heat sterilization is carried out within the homogenizer in which the homogenizer serves as a source of heating and pressurization for sterilization. The sterilization can also be carried out by sterile filtration of the solution and the second solvent before mixing and carrying out the subsequent steps under aseptic conditions. The method may also include the removal of the aqueous solvent to form a dry powder of the small particles. These processes are preferably used to prepare an aqueous suspension of small particles of a pharmaceutically active compound, sparingly soluble in water, suitable for in vivo delivery by an administrative route, such as parenteral, oral, pulmonary, nasal, buccal, topical, ophthalmic, rectal, vaginal, transdermal or similar. These and other aspects and attributes of the present invention will be discussed with respect to the following drawings and accompanying specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a schematic representation of a method of the present invention; FIG. 2 shows a schematic representation of another method of the present invention; FIG. 3 shows amorphous particles before homogenization; FIG. 4 shows particles after hardening by homogenization; FIG. 5 is an X-ray difractogram of itraconazole microprecipitated with polyethylene-660 glycol 12-hydroxystearate before and after homogenization; FIG. 6 shows crystals of Carbamazepine before homogenization; FIG. 7 microparticulate sample of Carbamazepine after homogenization (Avestin C-50); FIG. 8 is a diagram illustrating the Microprecipitation Process for Prednisolone; FIG. 9 is a photomicrograph of prednisolone suspension before homogenization; FIG. 10 is a photomicrograph of prednisolone suspension after homogenization; FIG. 1 1 illustrates a comparison of size distributions of nanosuspensions (this invention) and one. commercial fat emulsion; FIG. 12 shows X-ray diffraction patterns for itraconazole from raw material (upper part) and SMP-2-PRE (lower part). The raw material pattern has shifted upwards for clarity; FIG. 1 3a shows the DSC trace for itraconazole from raw material; FIG. 13b shows the DSC trace for SMP-2-PRE; FIG. 14 illustrates the DSC trace for SMP-2-PRE showing the fusion of the less stable polymorph after heating to 160 ° C, a recrystallization event after cooling and the subsequent fusion of the more stable polymorph after re-heating at 180 ° C; FIG. 15 Illustrates a comparison of SMP-2-PRE samples after homogenization. Solid line = sample seeded with itraconazole from raw material. Dotted line = sample not sown. The solid line has been displaced by 1 W / g for clarity; FIG. 16 illustrates the effect of sowing during precipitation. Dotted line = unseeded sample, solid line = sample seeded with itraconazole from raw material. The unseeded trace (dotted line) was moved upwards by 1.5 W / g for clarity; FIG. 1 7 illustrates the effect of seeding the drug concentrate through maturation. The upper X-ray diffraction pattern is for crystals prepared from fresh drug concentrate and is consistent with the stable polymorph (see FIG.12, top). The lower standard is for crystals prepared from matured drug concentrate (seeded), and is consistent with the metastable polymorph (see FIG 12, bottom). The upper pattern has shifted upward for clarity; FIG. 18 is a schematic diagram illustrating the combined and continuous solvent removal process for the production of an aqueous suspension of small particles that is essentially solvent-free; FIG. 1 9 is a schematic diagram illustrating a continuous solvent removal process for the production of an aqueous suspension of small particles, which is essentially solvent-free, by the use of cross-flow filtration; FIG. 20 is a schematic diagram illustrating a continuous solvent removal process for the production of an aqueous suspension of small particles of itraconazole that is essentially free of solvent; FIG. 21 is a graph illustrating NMP of scaling up of the process described in Example 19 of the laboratory scale of 200 mL to the pilot scale of 10 L; and FIG. 22 is a schematic diagram illustrating a continuous, combined process for the production of aqueous suspension of small particles substantially free of solvent.

DETAILED DESCRIPTION OF THE INVENTION The present invention is susceptible to modalities in many different forms. Preferred embodiments of the invention are set forth with the understanding that the present disclosure should be considered as exemplifications of the principles of the invention and is not intended to limit the broad aspects of the invention to the illustrated embodiments. The present invention provides compositions and methods for forming small particles of an organic compound, an organic compound for use in the process of this invention is any organic chemical entity whose solubility decreases from one solvent to another. This organic compound could be a pharmaceutically active compound, which can be selected from therapeutic agents, diagnostic agents, cosmetics, nutritional supplements and pesticides. The therapeutic agents may be selected from a variety of known pharmaceuticals such as, but not limited to: analgesics, anesthetics, analeptics, adrenergic agents, adrenergic blocking agents, adrenolitics, adrenocorticoids, adrenoimulants, anticholinergic agents, anticolinoesterases, anti-convulsants, agents alkylation, alkaloids, alloestheric inhibitors, anabolic steroids, anorexiantes, anti-acids, anti-diarrheic, antidotes, anticholics, antipyretics, anti-rheumatic agents, psychotherapeutic agents, neural blocking agents, anti-inflammatory agents, anti-helminthic , anti-arrhythmic agents, antibiotics, anti-coagulants, antidepressants, anti-diabetic agents, anti-epileptics, anti-fungal, anti-histamine, anti-hypertensive agents, anti-muscarinic agents, anti-mycobacterial agents, anti-malaria, antiseptics, anti-neoplastic agents, anti-protozoal agents, immunosuppressants, immune non-stimulators, anti-thyroid agents, anti-viral agents, anxiolytic sedatives, astringents, beta-adrenoceptor blocking agents, contrast media, corticosteroids, cough suppressants, diagnostic agents, diagnostic imaging agents, diuretics, dopaminergics , hemostats, hematological agents, hemoglobin modifiers, hormones, hypnotics, immunological agents, anti-hyperlipidemic and other lipid regulating agents, muscarinic, muscle relaxants, parasympathetic imitators, parathyroid calcitonin, prostaglandins, radiopharmaceuticals, sedatives, sex hormones, agents antiallergics, stimulants, sympathetic agents, thyroid agents, vasodilators, vaccines, vitamins and xanthines. Anti-neoplastic or anti-cancer agents include, but are not limited to, paclitaxel and derivative compounds, and other anti-neoplastic selected from the group consisting of alkaloids, antimetabolites, enzyme inhibitors, alkylating agents and antibiotics. The therapeutic agent can also be a biological agent, including, but not limited to, proteins, polypeptides, carbohydrates, polynucleotides and nucleic acids. The protein can be an antibody, which can be polyclonal or monoclonal. The diagnostic agents include the X-ray imaging agents and contrast medium. Examples of X-ray imaging agents include WIN-8883 (ethyl 3,5-diacetamido-2,4,6-triiodobenzoate) also known as ethyl ester of diatrazoic acid (EEDA), WIN 67722, it is to say, (6-ethoxy-6-oxohexyl-3,5-bis (acetamido) -2,4,6-triiodobenzoate; ethyl-2- (3,5-bis (acetamido) -2,4,6-triiodo- benzoyloxy) butyrate (WIN 16318); ethyl diatrizoxyacetate (WIN 12901); ethyl 2- (3,5-bis (acetamido) -2,4,6-triiodobenzoyloxy) propionate (WIN 16923); , 5-bis (acetamido) -2,4,6-triiodobenzoyloxy N-ethyl acetamide (WIN 65312); 2- (3,5-bis (acetamido) -2,4,6-triiodobenzoyloxy) isopropyl acetamide (WIN) 12855); diethyl 2- (3,5- bis (acetamido) -2,4,6-triiodobenzoyloxy malonate (WIN 67721); 2- (3,5-bis (acetamido) -2,4,6-triiodobenzoyloxy) ethyl phenylacetate (WIN 67585); propanedioic acid, [[3,5-bis (acetylamino) -2,4,5-triiodobenzoyl] oxy] bis (1-methyl) ester (WI N 68165); and benzoic acid, 3,5-bis (acetylamino) -2,4,6-triodo-4- (ethyl-3-ethoxy-2-butenoate) ester (WIN 68209). Preferred contrast agents include those that are expected to disintegrate relatively quickly under physiological conditions, thus reducing any inflammatory response associated with the particle. Disintegration can result from enzymatic hydrolysis, solubilization of carboxylic acids at physiological pH or other mechanisms. Thus, sparingly soluble iodinated carboxylic acids, such as iodipamide, diatrizoic acid, and metrizoic acid, may be preferred, together with hydrolytically labile iodinated species, such as WIN 67721, EIN 12901, WIN 68165 and WIN 68209 or others. Other contrast media include, but are not limited to, particulate preparations of adjuvants in magnetic resonance imaging such as gadolinium chelates or other paramagnetic contrast agents. Examples of such compounds are gadopentetate dimeglumine (Magnevist®) and gadoteridol (Prohance®).

A description of these classes of therapeutic agents and diagnostic agents and a list of species within each class can be found in Martindale, The Extra Pharmacopoeia, Twenty-ninth Edition, The Pharmaceutical Press, London, 1989, which is incorporated herein by reference. reference and becomes part of it. Therapeutic and diagnostic agents are commercially available and / or can be prepared by techniques known in the art. A cosmetic agent is any active ingredient capable of having a cosmetic activity. Examples of these active ingredients may be, among others, emollients, humectants, free radical inhibiting agents, anti-inflammatories, vitamins, depigmentation agents, anti-acne agents, anti-seborrheic agents, keratolytics, thinning agents, skin coloring agents and agents. sunscreen, and in particular, linolic acid, retinol, retinoic acid, ascorbic acid, alkyl esters, polyunsaturated fatty acids, nicotinic esters, tocopherol nicotinate, non-saponifiable rice, soybean or shea, ceramides, hydroxy acids such as glycolic acid, selenium derivatives, anti-oxidants, beta-carotene, gamma-oryzanol and stearyl glycerate. Cosmetics are commercially available and / or can be prepared by techniques known in the art. Examples of nutritional supplements contemplated for use in the practice of the present invention include, but are not limited to, proteins, carbohydrates, water-soluble vitamins (eg, vitamin C, B-complex vitamins and the like), fat-soluble vitamins ( for example, vitamins A, D, E, K and the like) and herbal extracts. Nutritional supplements are commercially available and / or can be prepared by techniques known in the art. The term pesticide is understood to encompass herbicides, insecticides, acaricides, nematicides, ectoparasiticides and fungicides. Examples of classes of compounds to which the pesticide may belong in the present invention include ureas, triazines, triazoles, carbamates, phosphoric acid esters, dinitroanilines, morpholines, acylalanines, pyrethroids, benzyl acid esters, diphenylethers, and polycyclic halogenated hydrocarb Specific examples of pesticides in each of these classes are mentioned in Pesticide Manual, 9th Edition, British Crop Protection Council. Pesticides are commercially available and / or can be prepared by techniques known in the art. Preferably, the organic compound or the pharmaceutically active compound is sparingly soluble in water. What is meant by "sparingly soluble in water" is a solubility of the compound in water of less than about 10 mg / mL, and preferably less than 1 mg / mL. These poorly water soluble agents are more suitable for aqueous suspension preparatisince there are limited alternatives for formulating these agents in an aqueous medium.

The present invention can also be practiced with water-soluble pharmaceutically active compounds, by capture of these compounds in a solid carrier matrix (eg, polylactide-polyglycolide copolymers, albumin, starch) or by encapsulation of these compounds in a surrounding vesicle. which is impermeable to the pharmaceutical compound. This encapsulation vesicle can be a polymeric shell, such as polyacrylate. In addition, the small particles prepared from these water-soluble pharmaceutical agents can be modified to improve the chemical stability and control the pharmacokinetic properties of the agents by controlling the release of the agents from the particles. Examples of water soluble pharmaceutical agents include, but are not limited to, simple organic compounds, proteins, peptides, nucleotides, oligonucleotides and carbohydrates. The particles of the present invention have an average effective particle size of generally less than about 1000 μm, as measured by dynamic light diffusion methods, eg, photo-correlation spectroscopy, laser diffraction, low-angle laser light diffusion (LALLS), mid-angle laser light diffusion (MALLS), dimming methods of light (Coulter method, for example), rheology, or microscope (light or electron). However, the particles can be prepared in a wide range of sizes, such as from about 20 μm to about 10 nm, from about 10 μm to about 10 nm, from about 400 nm to about 50 nm, from about 200 nm to about approximately 50 nm or any range or combination of ranges in it. The effective, average, preferred particle size depends on factors such as the proposed route of administration, formulation, solubility, toxicity and bioavailability of the compound. To be suitable for parenteral administration, the particles preferably have an average effective particle size of less than about 7 μm, and more preferably less than about 2 μm or any range or combination of ranges therein. Parenteral administration includes intravenous, intra-arterial, intrathecal, intraperitoneal, intraocular, intra-articular, intradural, intraventricular, intrapericardial, intramuscular, intradermal or subcutaneous injection. The particle sizes for oral dosage forms can be more than 2 μm. The particles may vary in size up to about 100 μm, taking into account that the particles have sufficient bioavailability and other characteristics of an oral dosage form. Oral dosage forms include tablets, capsules, caplets, soft and hard gel capsules, or other delivery vehicle for the delivery of a drug by oral administration. The present invention is further suitable for the proportion of particles of the organic compound in a form suitable for pulmonary administration. The particle sizes for pulmonary dosage forms can be more than 500 nm and typically less than about 10 μm. The particles in the suspension can be aerosolized and administered by a nebulizer for pulmonary administration. Alternatively, the particles can be administered as dry powder by a dry powder inhaler after removing the liquid phase from the suspension or the dry powder can be re-suspended in a non-aqueous propellant for administration by a metered dose inhaler. An example of a suitable propellant is a hydrofluorocarbon (HFC), such as HFC-134a (1, 1, 1, 2-tetrafluoroethane) and HFC-227ea (1,1,1,3,3,3-heptafluoropropane) . Unlike chlorofluorocarbons (CFCs), HFCs exhibit little or no ozone depletion potential; Dosage forms for other delivery routes, such as nasal, topical, ophthalmic, nasal, buccal, rectal, vaginal, transdermal and the like can also be formulated from the particles made from the present invention. The processes for the preparation of the particles can be separated into four general categories. Each of the process categories shares the steps of: (1) dissolving an organic compound in a water-miscible first solvent to create a first solution, (2) mixing the first solution with a second water solvent in order to precipitate the organic compound to create a pre-suspension, and (3) add energy to the pre-suspension in the form of high shear mixing or heat, or a combination of both, in order to provide a stable form of the organic compound that has the Desired size ranges, defined above. The mixing steps and the energy addition step can be carried out in consecutive stages or simultaneously. Process categories are distinguished based on the physical properties of the organic compound, as determined through X-ray diffraction studies, differential scanning calorimetry (DSC) studies, or other suitable study, conducted prior to the addition of energy and after the energy addition stage. In the first process category, before the energy addition stage, the organic compound in the pre-suspension takes an amorphous form, a semi-crystalline form or a super-cooled liquid form and has an average effective particle size . After the energy addition step, the organic compound is in a crystalline form having an effective average particle size essentially equal to or less than the pre-suspension. In the second process category, before the energy addition step, the organic compound is in a crystalline form and has an average effective particle size. After the energy addition step, the organic compound is in a crystalline form having essentially the same average effective particle size as before the energy addition stage but the crystals, after the energy addition step. , they are more likely to form aggregates. The minor tendency of the organic compound to form aggregates is observed by dynamic diffusion of light by laser and light microscope. In the third process category, before the energy addition stage, the organic compound is in a crystalline form which is friable and has an average effective particle size. What is meant by the term "friable" is that the particles are brittle and fracture more easily into smaller particles. After the energy addition step, the organic compound is in a crystalline form having an average effective particle size smaller than the crystals of the pre-suspension. By taking the steps necessary to place the organic compound in a crystalline form that is friable, the subsequent stage of energy addition can be carried out more quickly and efficiently when compared to an organic compound in a less friable crystalline morphology. In the fourth category of the process, the first solution and the second solvent are subjected simultaneously to the energy addition stage. In this way, the physical properties of the organic compound before and after the energy addition step were not measured. The stage of. The addition of energy can be carried out in any manner in which the pre-suspension or the first solution and the second solvent are exposed to cavitation, shearing or impact forces. In a preferred form of the invention, the energy addition step is a tempering step. Tempering is defined in this invention as the process of converting matter that is thermodynamically unstable into a more stable form by the individual or repeated application of energy (direct heat or mechanical stress), followed by thermal relaxation. This decrease in energy can be achieved by converting the solid form from a less ordered lattice structure to a more ordered one. Alternatively, this stabilization can occur by rearrangement of the surfactant molecules at the solid-liquid interface. These four process categories will be discussed separately below. It should be understood, however, that the process conditions, such as the surfactant or surfactant combination options, amount of surfactant used, reaction temperature, mixing speed of the solutions, rate of precipitation and the like, can be selected from order to allow any drug to be processed under any of the categories discussed below. The first process category, as well as the second, third, and fourth process categories, can further be divided into two sub-categories, Method A and B, shown schematically in FIGS. 1 and 2. The first solvent according to the present invention is a solvent or mixture of solvents in which the organic compound of interest is relatively soluble and which is miscible with the second solvent. Such solvents include, but are not limited to, water-miscible protic compounds, in which a hydrogen atom in the molecule is attached to an electronegative atom such as oxygen, nitrogen or other Group VA, VIA and Vi l A in the Periodic Table of The elements. Examples of such solvents include, but are not limited to, alcohols, amines (primary or secondary), oximes, hydroxamic acids, carboxylic acids, sulfonic acids, phosphonic acids, phosphoric acids, amides and ureas. Other examples of the first solvent also include aprotic organic solvents. Some of these aprotic solvents can form hydrogen bonds with water, but they can only act as proton acceptors because they lack effective proton donor groups. One class of aprotic solvents is a dipolar aprotic solvent, as defined by the International Union of Pure and Applied Chemistry (IU PAC Compendium of Chemical Terminology, 2nd Ed., 1997): A solvent with a comparatively high relative permissive capacity (or constant dielectric), greater than about 15, and a dimensionable permanent dipole moment, which can not properly donate hydrogen atoms to form strong hydrogen bonds, for example, dimethyl sulfoxide. The bipolar aprotic solvents can be selected from the group consisting of: amides (completely substituted with oxygen atoms lacking oxygen), ureas (completely substituted without hydrogen atoms attached to nitrogen), ethers, cyclic ethers, nitriles, ketones, sulfones, sulfoxides, completely substituted phosphates, phosphonate esters, phosphoramides, nitro compounds and the like. Dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidinone (NMP), 2-pyrrolidinone, 1,3-dimethylimidazolidinone (DMI), dimethylacetamide (DMA), dimethylformamide (DMF), dioxane, acetone, tetrahydrofuran (THF), tetramethylenesulfone (sulfolane), acetonitrile, and hexamethylphosphoramide (HMPA), nitromethane, among others, are members of this class. The solvents can also be selected by being generally immiscible in water, but having sufficient solubility in water at low volumes (less than 10%) in order to act as a first solvent miscible in water at these reduced volumes. Examples include aromatic hydrocarbons, alkenes, alkanes, and halogenated aromatics, halogenated alkenes, and halogenated alkanes. Aromatics include, but are not limited to, benzene (substituted or unsubstituted) and monocyclic or polycyclic lows. Examples of substituted benzenes include, but are not limited to, xylenes (ortho, meta or para) and toluene. Examples of alkanes include, but are not limited to, hexane, neopentane, heptane, isooctane and cyclohexane. Examples of halogenated aromatics include, but without limitation, chlorobenzene, bromobenzene and chlorotoluene. Examples of halogenated alkanes and alkenes include, but are not limited to, trichloroethane, methylene chloride, ethylenedichloride (EDC), and the like. Examples of all classes of prior solvents include, but are not limited to, N-methyl-2-pyrrolidinone (also called N-methyl-2-pyrrolidone), 2-pyrrolidinone (also called 2-pyrrolidone), 1,3-dimethyl-2-imidazolidinone (DMI), dimethyl sulfoxide, dimethylacetamide, acetic acid, lactic acid, methanol, ethanol, isopropanol, 3-pentanol, n-propanol, benzyl alcohol, glycerol, butylene glycol (butanediol), glycol ethylene, propylene glycol, mono- and diacylated monoglycerides (such as glyceryl caprylate), dimethyl isosorbide, acetone, dimethylsulfone, dimethylformamide, 1,4-dioxane, tetramethylenesulfone (sulfolane), acetonitrile, nitromethane, tetramethylurea, hexamethylphosphoramide (HMPA ), tetrahydrofuran (THF), dioxane, diethyl ether, tert-butylmethyl ether (TBME), aromatic hydrocarbons, alkenes, alkanes, halogenated aromatics, halogenated alkenes, halogenated alkanes, xylene, toluene, benzene, substituted benzene, ethyl acetate, acetate of methyl, butyl acetate, chlorobenzene, bromobenzene, chlorotoluene, trichloroethane, methylene chloride, ethylenedichloride (EDC), hexane, neopentane, heptane, isooctane, cyclohexane, polyethylene glycol (PEG, for example, PEG-4, PEG-8, PEG-9, PEG-12, PEG-14, PEG-16, PEG-120, PEG-75, PEG-150), polyethylene glycol esters (examples such as PEG dilaurate -4, PEG-20 dilaurate, PEG-6 isostearate, PEG-8 palmito-stearate, PEG-150 palmito-stearate), polyethylene glycol sorbitans (such as sorbitan isostearate PEG-20), polyethylene glycol monoalkyl ethers (examples such as dimethyl ether) of PEG-3, PEG-4 dimethyl ether), polypropylene glycol (PPG), polypropylene alginate, PPG-1 butanediol, methyl glucose ether of PPG-10, methyl glucose ether of PPG-20, PPG-15 stearyl, propylene glycol dicaprylate / dicaprate, propylene glycol laurate, and glycofurol (polyethylene glycol ether of tetrahydrofurfuryl alcohol). A first preferred solvent is N-methyl-2-pyrrolidinone. Another preferred first solvent is lactic acid. The second solvent is an aqueous solvent. This aqueous solvent can be water itself. This solvent may also contain regulators, salts, surfactant (s), water soluble polymers and combinations of these excipients.

Method A In Method A (see Fig. 1), the organic compound ("drug") is first dissolved in the first solvent in order to create a first solution. The organic compound can be added from about 0.1% (w / v) to about 50% (w / v) depending on the solubility of the organic compound in the first solvent. Heating the concentrate from about 30 ° C to about 100 ° C may be necessary to ensure complete dissolution of the compound in the first solvent. A second aqueous solvent is provided with one or more optional surface modifiers, such as an anionic surfactant, a cationic surfactant, a nonionic surfactant or a biologically active surface molecule added thereto. Suitable anionic surfactants include, but are not limited to, alkyl sulfonates, alkyl phosphates, alkyl phosphonates, potassium laurate, triethanolamine stearate, sodium lauryl sulfate, sodium dodecyl sulfate, alkyl polyoxyethylene sulfates, sodium alginate, sulfosuccinate dioctyl sodium, phosphatidylcholine, phosphatidylglycerol, phosphatidylinosine, phosphatidylserine, phosphatidic acid and its salts, glyceryl esters, sodium carboxymethylcellulose, cholic acid and other bile acids (eg, cholic acid, deoxycholic acid, glycocholic acid, taurocholic acid, glycoxycholic acid ) and salts thereof (eg, sodium deoxycholate, etc.). Suitable cationic surfactants include, but are not limited to, quaternary ammonium compounds, such as benzalkonium chloride, cetyltrimethylammonium bromide, chitosans, lauryldimethylbenzyl ammonium chloride, acylcarnitine hydrochlorides, or alkylpyridinium halides. Phospholipids can be used as anionic surfactants. Suitable phospholipids include, for example, phosphatidylcholine, phosphatidylethanolamine, diacylglycero-phosphoethanolamine (such as dimyritoyl-glycero-phosphoethanolamine (DMPE)., dipalmitoyl-glycero-phosphoethanolamine (DPPE), distearoyl-glycero-phosphoethanolamine (DSPE) and dioleolyl-glycero-phosphoethanolamine (DOPE)), phosphatidylserine, phosphatidylinositol, phosphatidylglycerol, phosphatidic acid, lysophospholipids, egg or soybean phospholipid, or a combination of them. The phospholipid can be salted or desalinated, hydrogenated or partially hydrogenated or be natural, semi-synthetic or synthetic. The phospholipid can also be conjugated with a water soluble or hydrophilic polymer. A preferred polymer is polyethylene glycol (PEG), which is also known as monomethoxy polyethylene glycol (mPEG). The molecular weights of the PEG can vary, for example, from 200 to 50,000. Some commonly used PEGs that are commercially available include PEG 350, PEG 550, PEG 750, PEG 1000, PEG 2000, PEG 3000, and PEG 5000. The phospholipid or the PEG-phospholipid conjugate can also incorporate a functional group that can be attached covalently to a ligand including, but not limited to, proteins, peptides, carbohydrates, glycoproteins, antibodies or pharmaceutically active agents. These functional groups can be conjugated to the ligands through, for example, amide bond, disulfide or thioether formation, or biotin / streptavidin bond. Examples of the ligand-binding functional groups include, but are not limited to, hexanoylamine, dodecamylamine, 1,12-dodecanedicarboxylate, thioethanol, 4- (p-maleimidophenyl) butyramide (MPB), 4- (p-maleimidomethyl) cyclohexane-carboxamide. (MCC), 3- (2-pyridylthio) propionate (PDP), succinate, glutarate, dodecanoate and biotin. Suitable nonionic surfactants include: polyoxyethylene fatty alcohol ethers (Macrogol and Brij), polyoxyethylene sorbitan fatty acid esters (Polysorbates), polyoxyethylene fatty acid esters (Myrj), sorbitan esters (Span), monostearate glycerol, polyethylene glycols, polypropylene glycols, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, arylalkyl polyether alcohols, polyoxyethylene-polyoxypropylene copolymers (poloxamers), poloxamines, methylcellulose, hydroxymethylceiulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, non-crystalline cellulose, polysaccharides they include starch and starch derivatives, such as hydroxyethyl starch (HES), polyvinyl alcohol, and polyvinyl pyrrolidone. In a preferred form of the invention, the nonionic surfactant is a copolymer of polyoxyethylene and polyoxypropylene and preferably a block copolymer of propylene glycol and ethylene glycol. Such polymers are sold under the tradename POLOXAMER also sometimes referred to as PLURONIC® and sold by various suppliers, including Spectrum Chemical and Ruger. Polyoxyethylene fatty acid esters include those having short alkyl chains. An example of such a surfactant is SOLUTOL® HS 15, polyethylene-660-hydroxystearate, manufactured by BASF Aktiengesellschaft. Biological molecules active on the surface include such molecules as albumin, casein, hirudin or other suitable proteins. Biological polysaccharides are also included and consist of, but not limited to, starches, heparin and chitosans. It may also be desirable to add a pH adjusting agent to the second solvent, such as sodium hydroxide, hydrochloric acid, tris or citrate regulator, acetate, lactate, meglumine or the like. The second solvent should have a pH within the range of from about 3 to about 1 1. For oral dosage forms, one or more of the following excipients may be used: gelatin, casein, lecithin (phosphatides), acacia gum, cholesterol, tragacanth, stearic acid, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene alkyl ethers, for example, macrogol ethers such as cetomacrogol 1000, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, for example, the commercially available Teens ™, polyethylene glycols, polyoxyethylene stearates, colloidal silicon dioxide, phosphates, sodium dodecylsulfate, carboxymethylcellulose calcium, carboxymethylcellulose sodium, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose phthalate, non-crystalline cellulose, magnesium aluminum silicate, triethanolamine, polyvinyl alcohol (PVA), and polyvinylpyrrolidone (PVP). The majority of these excipients are described in detail in the Pharmaceutical Excipients Manual, published jointly by the American Pharmaceutical Association and the Pharmaceutical Society of Great Britain, the Pharmaceutical Press, 1986. Surface modifiers are commercially available and / or can be prepared by techniques known in the art. Two or more surface modifiers can be used in combination. In a preferred form of the invention, the method for preparing small particles of an organic compound includes the steps of adding the first solution to the second solvent. The rate of addition depends on the size of the batch and the kinetics of precipitation for the organic compound. Typically, for a small-scale laboratory process (1 liter preparation), the rate of addition is from about 0.05 cc per minute to about 10 cc per minute. During the addition, the solutions must be under constant agitation. It has been observed through the use of a light microscope that amorphous particles, semi-crystalline solids or a super-cooled liquid are formed in order to create a pre-suspension. The method further includes the step of attaching the pre-suspension to an energy addition step in order to convert the amorphous particles, super cooled liquid or semi-crystalline solid into a more stable crystalline solid state. The resulting particles will have average particle sizes as measured by dynamic light diffusion methods (e.g., photo-correlation spectroscopy, laser diffraction, low-angle laser light diffusion (LALLS), medium-angle laser light diffusion (MALLS), methods of dimming light (Coulter method, for example), rheology or microscope (light or electrons) within the ranges established above). In process category four, the first solution and the second solvent are combined while conducting the driving-adding energy stage simultaneously. The energy addition step involves the addition of energy through sonication, homogenization, countercurrent flow homogenization, microfiuidization or other methods to provide forces that provide impact, shear or cavitation. The sample may be cooled or heated during this stage. In a preferred form of the invention, the energy addition step is affected by a piston interval homogenizer such as that sold by Avestin., Inc. under the product designation Emuls¡Flex-C160. In another preferred form of the invention, the energy addition step can be carried out by ultrasonication through the use of an ultrasonic processor, such as the Vibra-Cell Ultrasonic Processor (600 W), manufactured by Sonios and Materials, Inc. In still another preferred form of the invention, the energy addition step can be carried out by the use of an emulsification apparatus as described in U.S. Patent No. 5,720,551, which is incorporated herein by reference and is incorporated herein by reference. it is part of it. Depending on the rate of energy addition, it may be desirable to adjust the temperature of the processed sample to within the range of from about -30 ° C to 30 ° C. Alternatively, in order to effect a desired phase change in the processed solid, it may also be necessary to heat the pre-suspension to a temperature in the range of from about 30 ° C to about 1000 ° C during the addition step of energy.

Method B Method B differs from Method A in the following aspects. The first difference is that a surfactant or combination of surfactants is added to the first solution. The surfactants can be selected from the groups of anionic, nonionic, cationic surfactants and biological surface active modifiers set forth above.

Comparative Example of Method A and Method B and USPN 5,780,062 U.S. Patent No. 5,780,062 discloses a process for the preparation of small particles of an organic compound by first dissolving the compound in a suitable first solvent, water miscible. A second solution is prepared by dissolving a polymer and an amphiphile in an aqueous solvent. The first solution is then added to the second solution in order to form a precipitate consisting of an organic compound and a polymer-amphiphile complex. Patent '062 does not disclose the use of the energy addition step of this invention in Methods A and B. The lack of stability is typically made evident by the rapid aggregation and growth of particles. In some cases, the amorphous particles are recrystallized as large crystals. The addition of energy to the pre-suspension in the manner set forth above typically produces particles that exhibit decreased rates of particle aggregation and growth, as well as the absence of recrystallization after storage of the product.

Methods A and B are further distinguished from the process of the '062 patent by the absence of a polymer-amphiphilic complex formation step prior to precipitation. In Method A, such a complex can not be formed as long as no polymer is added to the diluent (aqueous) phase. In Method B, the surfactant, which can also act as an amphiphile, or polymer, is dissolved with the organic compound in the first solvent. This prevents the formation of any amphiphilic-polymer complex prior to precipitation. In the '062 patent, the successful precipitation of small particles depends on the formation of an amphiphilic-polymer complex before precipitation. The '062 patent discloses that the amphiphilic-polymer complex forms aggregates in the second aqueous solution. Patent '062 explains that the hydrophobic organic compound interacts with the amphiphilic-polymer complex, thereby reducing the solubility of these aggregates and causing precipitation. In the present invention, it has been shown that the inclusion of the surfactant or polymer in the first solvent (Method B) leads, after the subsequent addition to the second solvent, to the formation of a finer, more uniform particulate that is produced by the process outlined by the '062 Patent. For this purpose, two formulations were prepared and analyzed. Each of the formulations has two solutions, a concentrate and an aqueous diluent, which are mixed together and then sonicated. The concentrate in each formulation has an organic compound (itraconazole), a water miscible solvent (N-methyl-2-pyrrolidone or NMP) and possibly a polymer (poloxamer 1 88). The aqueous diluent has water, a tris regulator and possibly a polymer (poloxamer 188) and / or a surfactant (sodium deoxycholate). The average particle diameter of the organic particle is measured before sonication and after sonication. The first formulation A has itraconazole and NMP as a concentrate. The aqueous diluent includes water, poloxamer 188, tris regulator and sodium deoxycholate. Thus, the aqueous diluent includes a polymer (poloxamer 188) and an amphiphile (sodium deoxycholate), which can form a polymer / amphiphile complex and, accordingly, is found in accordance with the disclosure of the '062 Patent . (However, again Patent '062 does not disclose a stage of energy addition). The second formulation B has as a concentrate, itraconazole, NMP and poloxamer 1 88. The aqueous diluent includes water, tris regulator and sodium deoxycholate. This formulation is made according to the present invention. Since the aqueous diluent does not contain a combination of a polymer (poloxamer) and an amphiphile (sodium deoxycholate), a polymer / amphiphile complex can not be formed before the mixing step. Table 1 shows the average particle diameters, measured by laser diffraction in three reproduced suspension preparations. An initial size determination was made, after which the sample was sonicated for 1 minute. The size determination was then repeated. The large size reduction after sonication of Method A was indicative of the particle aggregation. Table 1 : A drug suspension resulting from the application of the processes described in this invention can be administered directly as an injectable solution, taking into account that Water For Injection is used in the formulation and a suitable medium is applied for sterilization of the solution. The sterilization can be carried out by methods well known in the art, such as steam or heat sterilization, gamma radiation and the like. Other sterilization methods, especially for particles in which more than 99% of the particles are less than 200 nm, would also include pre-filtration through a 3.0 micron filter followed by filtration through a 0.45 particle filter. microns, followed by steam or heat sterilization or sterile filtration through two redundant 0.2 micron membrane filters. Still another means of sterilization is the sterile filtration of the concentrate prepared from the first solvent containing drug and surfactant or optional surfactants and sterile filtration of the aqueous diluent. These are then combined in a sterile mixing container, preferably in a sterile, isolated environment. Further mixing, homogenization and processing of the suspension are then carried out under aseptic conditions. Yet another method for sterilization would be thermal sterilization or autoclaving within the homogenizer itself, before, during or after the homogenization step. The processing after this heat treatment would be carried out under aseptic conditions. Optionally, a solvent-free suspension can be produced by removal of the solvent after precipitation. This can be carried out by centrifugation, dialysis, diafiltration, force field fractionation, high pressure filtration, reverse osmosis or other separation techniques well known in the art. The complete removal of N-methyl-2-pyrrolidinone was typically carried out by one to three successive centrifugation runs; after each centrifugation (1 8,000 rpm for 30 minutes) the supernatant was decanted and discarded. A fresh volume of the suspension vehicle without the organic solvent was added to the remaining solids and the mixture dispersed by homogenization. It will be recognized by those skilled in the art that other high shear mixing techniques could be applied in this stage of reconstitution. Alternatively, solvent-free particles can be formulated in various dosage forms, as desired for a variety of administrative routes, such as oral, pulmonary, nasal, topical, intramuscular and the like. In addition, any unwanted excipients, such as surfactants, can be replaced by a more desirable excipient by using the separation methods described in the preceding paragraph. The solvent and the first excipient can be discarded with the supernatant after centrifugation or filtration. A fresh volume of the suspension vehicle without the solvent and without the first excipient can also be added. Alternatively, a new surfactant may be added. For example, a suspension consisting of drug, N-methyl-2-pyrroidinone (solvent), poloxamer 188 (first excipient), sodium deoxycholate, glycerol and water can be replaced with phospholipids (new surfactant), glycerol and water after the centrifugation and removal of the supernatant.

I. First Process Category The methods of the first process category generally include the step of dissolving the organic compound in a first water-miscible solvent followed by the step of mixing this solution with an aqueous solvent in order to form a pre-suspension. wherein the organic compound is in an amorphous form, a semi-crystalline form or in a supercooled liquid form, as determined by X-ray diffraction studies, DSC, light microscopy or other analytical techniques and has a Average effective particle size within one of the effective particle size ranges, above established. The mixing step is followed by a step of adding energy.

I. Second Process Category The methods of the second process category include essentially the same stages as the stages of the first process category but differ in the following aspect. An X-ray diffraction, DSC or other suitable analytical techniques of the pre-suspension show in organic compound in a crystalline form and having an average effective particle size. The organic compound after the energy addition step has essentially the same average effective particle size as before the energy addition stage but has less tendency to form aggregates of larger particles when compared to that of the prepartion particles. -suspension. Without relating to a theory, it is believed that the differences in particle stability may be due to a rearrangement of the surfactant molecules at the solid-liquid interface. ll l. Third Process Category The methods of the third process category modify the first two stages of those of the process categories, first and second, in order to ensure that the organic compound in the pre-suspension is in a friable form that has an average effective particle size (e.g., such as thinner needles and thin plates). The friable particles can be formed by selection of suitable solvents, surfactants or combination of surfactants, the temperature of the individual solutions, the mixing speed and the rate of precipitation and the like. The friability can also be improved by the introduction of grid defects (eg, dissociation planes) during the steps of mixing the first solution with the aqueous solvent. This would arise from the rapid crystallization, such as that produced in the precipitation stage. In the energy addition stage, these friable crystals are converted into crystals that are kinetically stabilized and have an average effective particle size smaller than those of the pre-suspension. The kinetically stabilized average particles have a reduced tendency to form aggregates when compared to particles that do not kinetically stabilize. In such a case, the energy addition step results in the fractionation of the friable particles. By ensuring that the particles of the pre-suspension are in a friable state, the organic compound can be prepared more easily and quickly in a particle within the desired size ranges when compared to the processing of an organic compound where the stages have not been taken to turn them into a friable form.

IV. Fourth Process Category The methods of the fourth process category include the stages of the first process category except that the mixing step is carried out simultaneously with the energy addition stage.

Polymorphous Control The present invention also provides additional steps to control the crystal structure of an organic compound to finally produce a suspension of the compound in the desired size range and a desired crystal structure. What is meant by the term "crystal structure" is the installation of the atoms within the unit cell of the crystal. The compounds that can be crystallized in different crystal structures are said to be polymorphic. The identification of polymorphs is important in the formulation of drugs since different polymorphs of the same drug can show differences in solubility, therapeutic activity, bioavailability and stability of the suspension. According to the above, it is important to control the polymorphic form of the compound to ensure the purity of the product and the ability to reproduce batch in batch. Steps to control the polymorphic form of the compound include seeding the first solution, the second solvent or the pre-suspension in order to ensure the formation of the desired polymorph. Seeding includes the use of a seed compound or addition energy. In a preferred form of the invention, the seed compound is a pharmaceutically active compound in the desired polymorphic form. Alternatively, the seed compound can also be an inert impurity, a compound not related in structure with the desired polymorph but with characteristics that can lead to the tempering of a crystal core or an organic compound with a structure similar to that of the polymorph wanted. The seed compound can be precipitated from the first solution. This method includes the steps of adding the organic compound in an amount sufficient to exceed the solubility of the organic compound in the first solvent in order to create an over saturated solution. The saturated solution is treated to precipitate the organic compound in the desired polymorphic form. The treatment of the super-saturated solution includes the maturation of the solution for a period of time until the formation of a crystal or crystals is observed to create a seed mixture. It is also possible to add energy to the super saturated solution to cause the organic compound to precipitate from the solution in the desired polymorph. The energy can be added in a variety of ways, including the energy addition stages described above. Additional energy can be added by heating or by exposing the pre-suspension to electromagnetic energy sources, particle beam or electron beam. Electromagnetic energy includes light energy (ultraviolet, visible or infrared) or coherent radiation, such as that provided by a laser, microwave energy such as that provided by a maser (microwave amplification by stimulated emission of radiation), electromagnetic energy. dynamic or other sources of radiation. Also contemplated is the use of ultrasound, a static electric field, or a static magnetic field or combinations thereof, as the source of energy addition. In a preferred form of the invention, the method for producing seed crystals from a mature supersaturated solution includes the steps of: (i) adding an amount of an organic compound to the first organic solvent in order to create a supersaturated solution, ( I) ripen the supersaturated solution in order to form detectable crystals to create a seed mixture; Y (iii) mixing the seed mixture with the second solvent to precipitate the organic compound in order to create a pre-suspension. The pre-suspension can then be processed as described above in detail in order to provide an aqueous suspension of the organic compound in the desired polymorph and in the desired size range. Seeding can also be carried out by adding energy to the first solution, the second solvent or the pre-suspension as long as the liquid or exposed liquids contain the organic compound or a seed material. The energy can be added in the same way as described above for the supersaturated solution. Accordingly, the present invention provides a composition of matter of an organic compound in a desired polymorphic form essentially free of the polymorph or unspecified polymorphs. In a preferred form of the present invention, the organic compound is a pharmaceutically active substance. One such example is set forth in Example 16 below where sowing during microprecipitation provides a polymorph of traconazole essentially free of the polymorph of raw material. It is contemplated that the methods of this invention can be used to selectively produce a desired polymorph for numerous pharmaceutically active compounds.

Combined and Continuous Process for the Production of Aqueous Suspension of Small Particles The small particles of the present invention can also be prepared as an aqueous suspension essentially free of solvents by a combined and continuous process in which microprecipitation is combined with homogenization and simultaneous continuous removal of the first miscible solvent in water, which is generally an organic solvent (referred to as "solvent" hereinafter in this section and related Examples 19-25, unless otherwise specified). The presence of solvents is undesirable in suspensions, especially for therapeutic use. It is known that solvents improve the Oswald maturation of the particles in the suspension, leading to an increased particle size and poor stability induced by the addition of particles. This phenomenon typically begins immediately after nucleation and is further catalyzed by higher temperatures that are common during the energy addition stage, such as high pressure homogenization, sonication, and other particle size reduction processes-however, a process which involves the continuous removal of solvent during the reduction of particles can be beneficial in obtaining particles that are small and stable. In addition, such a continuous process will reduce processing time, provide consistency and control of the process and eliminate the need for additional stages of particle size reduction after solvent removal. Such a process is also easy to perform at scale. In this combined and continuous process, the solvent is removed simultaneously and continuously while the particles are formed from the combined stages of microprecipitation and homogenization. This process differs from previously described methods or other microprecipitation methods since this process does not require an additional and separate stage of solvent removal after finishing the particle formation stage. Common solvent removal processes, such as centrifugation, often induce particle aggregation, which may require an additional stage of particle size reduction to fracture the aggregates after the solvent removal stage. The combined and continuous process produces an aqueous suspension of the small particles, which is essentially free of any residual organic solvent. What is meant by "essentially free of any residual organic solvent" is that the aqueous suspension contains less than about 100 ppm of the solvent, more preferably less than about 50 ppm of the solvent and more preferably less than about 10 ppm of the solvent. The process, illustrated schematically in FIG. 18, generally includes (i) dissolving the organic compound in a first water-miscible solvent to form a drug solution (also known as a drug concentrate); (ii) mixing the solution with a second solvent that is aqueous (the anti-solvent), in order to form a mixture that initiates the microprecipitation process; and (Mi) simultaneously homogenizing the mixture and continuously removing the first solvent from the mixture. Step (iii) is repeated until small particles are formed in the aqueous suspension, having an average effective particle size of less than about 100 μm. The microprecipitation step can be carried out simultaneously with the homogenization / solvent removal stage. The obtained aqueous suspension is essentially free of the first solvent. The first water miscible solvent is generally an organic solvent, which may be a protic organic solvent or an aprotic organic solvent, as previously described in the present application. A preferred solvent is N-methyl-2-pyrrolidinone (NMP). Another preferred solvent is lactic acid. In a preferred embodiment, the process further includes mixing one or more surface modifiers in the first water-miscible solvent or the second aqueous solvent, or both the first water-miscible solvent and the second aqueous solvent. Continuous homogenization and removal of solvent simultaneously can be initiated immediately after the initiation of microprecipitation when the drug solution and the second aqueous solvent are mixed. Alternatively, the homogenization and the continuous withdrawal of. solvent can be carried out simultaneously while the drug solution and the second solvent are mixed. In both cases, solvent removal is conducted on a continuous basis until the end of the process when the aqueous suspension is substantially free of the first solvent. The size of the particle in the present invention is generally less than about 100 μm, as measured by dynamic light diffusion methods, eg, photo-correlation spectroscopy, laser diffraction, low-angle laser light diffusion (LALLS). , medium angle laser light diffusion (MALLS), light dimming methods (Coulter method, for example), rheology, or microscope (light or electrons). However, the particles can be prepared in a wide range of sizes, such as from about 20 μm to about 10 nm, from about 1 μm to about 10 nm, from about 2 μm to about 10 nm, from about 1 μm to about about 10 nm, from about 400 nm to about 50 nm, from about 200 nm to about 50 nm or any range or combination of ranges therein. The particle size can be controlled by controlling various factors such as, but not limited to, the rate of homogenization, the homogenization temperature, the homogenization time and the speed of removal of the solvent. Any homogenizer commercially available in the present invention can be used. An example of a suitable homogenizer is a piston-range homogenizer, such as that sold by Avestin I nc. under the product designation EmulsiFlex-C160. More than one homogenizer can be installed in series. Although various solvent removal techniques can be used for continuous removal of solvent in the present disclosure, the preferred technique is cross flow ultrafiltration. FIG. 19 is a schematic diagram illustrating a continuous solvent removal process for the production of an aqueous suspension of small particles, which is essentially free of solvent by the use of a cross flow ultrafiltration. As illustrated in FIG. 19, after mixing the drug solution in the water-miscible organic solvent (the drug concentrate) and the second aqueous solvent (the anti-solvent) to form a mixture, the mixture is immediately introduced into a homogenizer and homogenizes Simultaneously, the mixture is circulated by a recycling pump within a closed loop system from the homogenizer, through an ultrafiltration unit and back to the homogenizer. This recirculation repeats the number of cycles that are necessary until the aqueous suspension is substantially free of the first solvent miscible in water. The suspension is then collected from the homogenizer. The membrane used in ultrafiltration is preferably sterilizable and responsible for cleaning processes. Suitable membranes include, but are not limited to, polymer membranes (including, but not limited to, polysulfone and cellulose membranes) and ceramic membranes. Ceramic membranes are particularly desirable for solvents, such as NMP, which are not compatible with polymer membranes. Preferably, the cross-flow filtration membranes have molecular weight cuts of from about 300,000 nm to about 10 nm. The molecular weight cutoff of the membrane usually depends on the size. of the prepared particles. In one embodiment, the flow cross ultrafiltration also includes a "backward pulse" operation, wherein the infiltrate flow in the cross-flow membrane is reversed for a short period of time (one pulse), in order to dislodge particles that are forming cakes on the surface of the membrane. Ultrafiltration can be conducted in two stages in order to reduce processing time. The first stage is a concentration step to reduce the bulk volume in which a concentrate is prepared from the mixture. The second stage is a diafiltration step to remove the solvent as well as any soluble impurity. The method may further include sterilization of the aqueous suspension by, for example, thermal sterilization or gamma radiation. In one embodiment, the thermal sterilization is performed within the homogenizer in which the homogenizer serves as a source of heating and pressurization for sterilization. The sterilization can also be carried out by sterile filtration of the drug solution and the aqueous solvent prior to mixing and performing the subsequent steps under aseptic conditions. The method may also include the removal of the aqueous medium in the aqueous suspension to form a dry powder of the small particles. The dry powder is more suitable for the administration of small particles by inhalation of the pulmonary route. Alternatively, the dry powder may be resuspended in a medium suitable for other routes of administration, such as parenteral administration. An example of a suitable medium for parenteral administration is an aqueous medium, such as, but not limited to, saline or a regulator with a physiological pH.

Examples A. Examples of Process Category 1 Example 1: Preparation of itraconazole suspension by use of the Process 1 category. Method A with homogenization To a 3 L flask add 1680 mL of Water For Injection. Heat liquid to 60-65 ° C and then slowly add 44 grams of Pluronic F-68 (poloxamer 188) and 12 grams of sodium deoxycholate, stir after each addition to dissolve the solids. After the addition of solids is complete, stir for another 15 minutes at 60-65 ° C to ensure complete dissolution. Prepare a regulator of 50 mM tris (tromethamine) by dissolving 6.06 grams of tris in 800 mL of Water For Injection. Titrate this solution at pH 8.0 with 0.1 M hydrochloric acid. Dilute the resulting solution in 1 liter with water for additional injection. Add 200 mL of the tris regulator to the poloxamer / deoxycholate solution. Shake vigorously to mix the solutions. In a 150 mL beaker, add 200 grams of itraconazole and 120 mL of N-methyl-2-pyrrolidinone. Heat the mixture to 50-60 ° C and stir to dissolve solids. After the total dissolution is visually apparent, stir another 15 minutes to ensure complete dissolution. Cool the itraconazole-NMP solution at room temperature. Load a syringe pump (two 60 ml glass syringes) with the 120 mL of itraconazole solution previously prepared. Meanwhile, empty all the surfactant solution into a homogenizer hopper that has been cooled to 0-5 ° C (this can be done either by using a coated hopper through which circulates coolant or by means of a bypass). the hopper with ice). Place a mechanical stirrer in the surfactant solution so that the blades are completely submerged. Using the syringe pump, slowly add (1 -3 mL / min) all the itraconazole solution to the cooled, stirred surfactant solution. A stirring speed of ai;, less 700 rpm is recommended. An aliquot of the resulting suspension (Suspension A) is analyzed by light microscopy (Hoffman Modulation Contrast) and by laser diffraction (Horiba). Suspension A is observed by light microscopy to consist of approximately spherical amorphous particles (below 1 micron), either joined together in aggregates or moving freely by Brownian motion. See FIG. 3. Dynamic light diffusion measurements typically produce a bimodal distribution pattern that signifies the presence of aggregates (1 0-100 microns in size) and the presence of individual amorphous particles ranging from 200-700 nm in median particle diameter. The suspension is immediately homogenized (at 1 0,000 to 30,000 psi) for 10-30 minutes. At the end of the homogenization, the temperature of the suspension in the hopper does not exceed 75 ° C. The homogenized suspension is collected in 500 mL bottles, which are cooled immediately in the refrigerator (2-8 ° C). This suspension (Suspension B) is analyzed by light microscopy and is found to consist of elongated plate pecks with a length of 0.5 to 2 microns and an amplitude in the range of 0.2-1 microns. See FIG. 4. Dynamic light diffusion measurements typically indicate a median diameter of 200-700 nm.

Stability of Suspension A ("Pre-suspension") (Example 1) During the microscopic examination of the aliquot of Suspension A, the crystallization of the amorphous solid was observed directly. Suspension A was stored at 2-8 ° C for 12 hours and examined by light microscope. The gross visual inspection of the sample revealed severe flocculation, with some of the contents in the lower part of the container settling. Microscopic examination indicated the presence of large, plate-like crystals, elongated, about 10 microns in length.

Stability of Suspension B As opposed to the instability of Suspension A, Suspension B was stable at 2-8 ° C for the duration of the preliminary stability study (1 month). The microscope on the matured sample clearly showed that no significant change in the morphology or size of the particles had occurred. This was confirmed by light diffusion measurement.

Example 2: Preparation of itraconazole suspension by use of Process Category 1, Method A with ultrasonication To a 500 mL stainless steel vessel is added 252 mL of Water For Injection. The liquid is heated to 60-65 ° C and then 6.6 grams of Pluronic F-8 (poioxamer 188) and 0.9 grams of sodium deoxycholate are added slowly, with each addition stirring to dissolve the solids. After the addition of solids is complete, stir for another 15 minutes at 60-65 ° C to ensure complete dissolution. 50 mM of tris buffer (tromethamine) is prepared by dissolving 6.06 grams of tris in 800 mL of Water For Injection. This solution is titrated at pH 8.0 with 0.1 M hydrochloric acid. The resulting solution is diluted to 1 liter with additional water for injection. 30 mL of the tris buffer is added to the poloxamer / deoxycholate solution. Stir vigorously to mix the solutions. In a 30 mL container add 3 grams of itraconazole and 18 mL of N-methyl-2-pyrrolidone. The mixture is heated to 50-60 ° C and stirred to dissolve solids. After the total dissolution is visually apparent, stir another 15 minutes to ensure complete dissolution. The solution of itraconazole-NMP is cooled to room temperature. A syringe pump is charged with 1 8 mL of itraconazole solution prepared in a previous step. A mechanical stirrer is placed in the surfactant solution so that the blades are completely immersed. The container is cooled to 0-5 ° C by immersion in an ice bath. By using the syringe pump, all the itraconazole solution is slowly added (1 -3 m L / min) to the stirred, cooled surfactant solution. A stirring speed of at least 700 rpm is recommended. An ultrasonic horn is immersed in the resulting suspension so that the probe is approximately 1 cm above the bottom of the stainless steel vessel. It is sonicated (10,000 to 25,000 Hz, at least 400 W) for 15 to 20 minutes at 5 minute intervals. After the first 5 minute sonication, the ice bath is removed and additional sonication is carried out. At the end of the ultrasonication, the temperature of the suspension in the container does not exceed 75 ° C. The suspension is collected in a 500 mL Type I glass bottle, which is immediately cooled in the refrigerator (2-8 ° C). The characteristics of the particle morphology of the suspension before and after sonication were very similar to those observed in Method A before and after homogenization (see Example 1).

Example 3: Preparation of itraconazole suspension by use of Process Category 1. Method B with homogenization 50 mM of tris buffer (tromethamine) is prepared by dissolving 6.06 grams of tris in 800 mL of Water For Injection. This solution is titrated at pH 8.0 with 0.1 M hydrochloric acid. The resulting solution is diluted to 1 liter with Water for Additional Injection. To a 3 L flask, 1 680 mL of Water For I njection is added. 200 mL of the tris regulator is added to the 1680 mL of water. Stir vigorously to mix solutions. Into a 1 50 mL beaker are added 44 grams of Pluronic F-68 (poloxamer 188) and 12 grams of deoxycholate solution to 120 mL of N-methyl-2-pyrrolidinone. The mixture is heated to 50-60 ° C and stirred to dissolve solids. After the total dissolution is visually apparent, stir 1 5 minutes to ensure complete dissolution. To this solution, 20 grams of itraconazole are added, and it is stirred until it is completely dissolved. The solution of itraconazole-surfactant-NMP is cooled to room temperature. A syringe pump is loaded (two glass syringes of 60 mL) with the 120 mL of the concentrated itraconazole solution, previously prepared. Meanwhile, the tris diluted regulator solution, prepared above, is emptied into a homogenizer hopper that has been cooled down to 0-5 ° C (this can be done either through the use of a coated hopper through which circulate the refrigerant or by way of the hopper with ice). A mechanical stirrer is placed in the buffer solution so that the blades are completely submerged. By using the syringe pump, all the itraconazole-surfactant concentrate is added slowly (1 -3 mL / min) to the chilled, stirred buffer solution.

A stirring speed of at least 700 rpm is recommended. The resulting cooled suspension is immediately homogenized (at 10,000 to 30,000 psi) for 10-30 minutes. At the end of the homogenization, the temperature of the suspension in the hopper does not exceed 75 ° C. The homogenized suspension is collected in 500 mL bottles, which are cooled immediately in the refrigerator (2-8 ° C). The characteristics of the particle morphology of the suspension before and after homogenization are very similar to those observed in Example 1, except that in process category 1 B, the pre-homogenized material tended to form fewer aggregates and less size, which resulted in a much smaller overall particle size as measured by laser diffraction. After homogenization, the results of dynamic light diffusion were typically identical to those presented in Example 1.

Example 4: Preparation of itraconazole suspension by use of Process Category 1, Method B with ultrasonication To a 500 mL flask is added 252 mL of Water For Injection. 50 mM of tris buffer (tromethamine) is prepared by dissolving 6.06 grams of tris in 800 mL of Water For Injection. This solution is titrated at pH 8.0 with 0.1 M hydrochloric acid. The resulting solution is diluted to 1 liter with additional water for injection. 30 mL of the tris regulator is added to the water. Stir vigorously to mix the solutions. Into a 30 mL beaker are added 6.6 grams of Pluronic F-68 (poloxamer 188) and 0.9 grams of sodium deoxycholate to 1 8 mL of N-methyl-2-pyrrolidinone. The mixture is heated to 50-60 ° C and stirred to dissolve solids. After the total dissolution is visually apparent, stir another 15 minutes to ensure complete dissolution. To this solution is added 3.0 grams of itraconazole and it is stirred until it is completely dissolved. The solution of itraconazole-surfactant-NP is cooled to room temperature. A syringe pump (a 30 mL glass syringe) is charged with the 1 8 mL of the previously prepared concentrated itraconazole solution. A mechanical stirrer is placed in the buffer solution so that the blades are completely submerged. The container is cooled to 0-5 ° C by immersion in an ice bath. By using the syringe pump, all the itraconazole-surfactant concentrate is added slowly (1 -3 mL / min) to the chilled, stirred buffer solution. A stirring speed of at least 700 rpm is recommended. The resulting cooled suspension is sonicated immediately (1 0,000 to 25,000 psi, at least 400 W) for 15-20 minutes, at 5 minute intervals. After the first 5 minutes of sonication, the ice bath is removed and additional sonication is carried out. At the end of the ultrasonication, the temperature of the suspension in the hopper does not exceed 75 ° C. The resulting suspension is collected in a 500 mL bottle, which is immediately cooled in the refrigerator (2-8 ° C). The characteristics of the particle morphology of the suspension before and after sonication are very similar to those observed in Example 1, except that in process category 1, Method B, the pre-sonicated material tended to form fewer aggregates and of smaller size, which resulted in a much smaller overall particle size as measured by laser diffraction. After ultrasonication, the results of dynamic light diffusion were typically identical to those presented in Example 1.

B. Examples of Process Category 2 Example 5: Preparation of itraconazole suspension (1%) with 0.75% Solutol® HR (PEG-660 12-hydroxystearate) Process Category 2, Method B Solutol (2.25 g) and itraconazole (3.0 g) were weighed in a beaker and 36 mL of filtered N-methyl-2-pyrrolidinone (NMP) were added. This mixture was stirred under low heat (up to 40 ° C) for approximately 15 minutes until the solution ingredients dissolved. The solution was cooled to room temperature and filtered through a 0.2 micron filter under vacuum. Two 60 mL syringes were filled with the filtered drug concentrate and placed in a syringe pump. The pump was set to deliver approximately 1 mL / min of concentrate to a rapidly stirred aqueous regulator solution (400 rpm). The regulator solution consisted of 22 g / L of glycerol in 5 mM of tris buffer. Through all the addition of the concentrate, the regulator solution was maintained in an ice bath at 2-3 ° C. At the end of the precipitation, after the complete addition of concentrate to the regulator solution, approximately 100 mL of the suspension was centrifuged for 1 hour, the supernatant was discarded. The precipitate was resuspended in a solution of 20% NMP in water, and again centrifuged for 1 hour. The material was dried overnight in a vacuum oven at 25 ° C. The dried material was transferred to a flask and analyzed by X-ray diffractometry using chromium radiation (see FIG 5). Another 1 00 mL aliquot of the microprecipitated suspension is sonicated for 30 minutes at 20,000 Hz, 80% full amplitude (full amplitude = 600 W). The sonicated sample was homogenized in 3 equal aliquots, each for 45 minutes (Avestin C5, 2-5 ° C, 15,000-20,000 psi). The combined fractions were centrifuged for about 3 hours, the supernatant was removed and the precipitate was re-suspended in 20% NMP. The re-suspended mixture was centrifuged again (15,000 rpm at 5 ° C). The supernatant was decanted and the precipitate was dried under vacuum overnight at 25 ° C. The precipitate was subjected to analysis by X-ray diffractometry (see FIG 5). As shown in Fig. 5, the X-ray diffraction patterns of the processed samples, before and after homogenization, are essentially identical, still showing a significantly different pattern compared to the starting raw material. The unhomogenized suspension is unstable and agglomerates after storage at room temperature. The stabilization that occurs as a result of homogenization is believed to arise from the re-installation of surfactant on the surface of the particle. This re-installation should result in a lower propensity to add particles.

C. Examples of "Process Category" Example 6: Preparation of carbamazepine suspension by using Process Category 3, Method A with homogenization 2.08 g of carbamazepine were dissolved in 10 mL of NMP. 1.0 mL of this concentrate was subsequently dripped at 0.1 mL / min in 20 mL of a stirred solution of 1.2% lecithin and 2.25% glycerin. The temperature of the lecithin system was maintained at 2-5 ° C during the entire addition. The pre-dispersion was cooled after homogenizing (5-15 ° C) for 35 minutes at 15,000 psi. The pressure was increased to 23,000 psi and the homogenization continued for another 20 minutes. The particles produced by the process have a mean diameter of 0.881 μm with 99% of the particles being less than 2.24 μm.

Example 7: Preparation of 1% carbamazepine suspension with 0.125% Solutol® by using Process Category 3, Method B with homogenization A 20% carbamazepine drug concentrate and 5% glycocholic acid was prepared (Sigma Chemical Co.) in N-methyl-2-pyrrolidinone. The microprecipitation step involved the addition of the drug concentrate to the receptor solution (distilled water) at a rate of 0.1 mL / min. The receiving solution was stirred and maintained at about 5 ° C during the precipitation. After precipitation, the final ingret concentrations were 1% carbamazepine and 0.125% Solutol®. The drug crystals were examined under a microscope light by the use of positive phase contrast (400X). The precipitate consisted of fine needles approximately 2 microns in diameter and ranging from 50-150 microns in length. The homogenization (piston interval homogenizer) Avestin C-50) at approximately 20,000 psi for approximately 15 minutes resulted in small particles, less than 1 micron in size and largely without aggregates. The laser diffraction analysis (Horiba) of the homogenized material showed that the particles had an average size of 0.4 microns with 99% of the particles smaller than 0.8 microns. The low energy sonication, suitable to fracture agglomerated particles, but without enough energy to cause a decrease in the individual particles, of the sample prior to the Horiba analysis had no effect on the results (the numbers were the same with and without sonication). This result was consistent with the absence of particle agglomeration. The samples prepared by the above process were centrifuged and the supernatants were replaced with a replacement solution consisting of Solutol® at 0.125%. After centrifugation and replacement of the supernatant, the concentrations of suspension ingrets were 1% carbamazepine and 0.125% Solutol®. The samples were re-homogenized by homogenizer by piston interval and stored at 5 ° C. After 4 weeks of storage, the suspension had an average particle size of 0.751 with 99% less than 1.729. The numbers reported are from the Horiba analysis in non-sonicated samples.

Example 8: Preparation of 1% carbamazepine suspension with 0.06% sodium glycodeoxycholate and 0.06% poloxamer 188 by use of Process Category 3, Method B with homogenization. A drug concentrate comprising 20% carbamazepine was prepared and 5% glycodeoxycholate in N-methyl-2-pyrrolidinone. The microprecipitation step involved the addition of the drug concentrate to the receptor solution (distilled water) at a rate of 0.1 mL / min. Thus, the following examples demonstrate that the addition of a surfactant or other excipient to the aqueous precipitation solution in Methods A and B above is optional. The receiving solution was stirred and maintained at about 5 ° C during the precipitation. After precipitation, the final ingret concentrations were 1% carbamazepine and 0.125% Solutol®. The drug crystals were examined under a light microscope by using positive phase contrast (400X). The precipitate consisted of fine needles approximately 2 microns in diameter and ranging from 50-150 microns in length. The comparison of the precipitate with the raw material before precipitation reveals that the precipitation stage in the presence of a surface modifier (glycodeoxycholic acid) results in very thin crystals that are much thinner than the starting raw material (see FIG. . The homogenization (homogenizer by piston interval Avestin C50) at approximately 20, 000 psi for approximately 15 minutes results in small particles less than 1 micron in size and largely without aggregates. See FIG. 7. The laser diffraction analysis (Horiba) of the homogenized material showed that the particles had an average size of 0.4 microns with 99% of the particles smaller than 0.8 microns. The sonication of the sample before the Horiba analysis had no effect on the results (the numbers were the same with and without sonication). This result was consistent with the absence of particle agglomeration. The samples prepared by the above process were centrifuged and the supernatant solutions were replaced with a replacement solution consisting of 0.06% glycodeoxycholic acid (Sigma Chemical Co.) and 0.06% Poloxamer 1 88. The samples were re-homogenized by homogenizer by piston interval and stored at 5 ° C. After 2 weeks of storage, the suspension had an average particle size of 0.531 microns with 99% less than 1.114 microns. The numbers reported come from the Horiba analysis on non-sonicated samples. Mathematical Analysis (Example 8) of the force required to fractionate the precipitated particles compared to the force required to fracture particles of the starting raw material (carbamazepine): The amplitude of the largest crystals observed in the raw material of carbamazepine (FIG. 6, image on the left) are almost 1 0 times larger than the amplitude of crystals in the microprecipitated material (FIG. 6, image on the right). Assuming that the crystal thickness ratio (1: 10) is proportional to the crystal amplitude ratio (1: 10), then the moment of force required to dissociate the larger crystal in the raw material should be approximately 1,000 times greater than the force required to fracture the microprecipitated material, since: e = 6PL / (Ewx2) Equation 1 where, eL = longitudinal deformation required to fracture the crystal ("yield value") P = beam load L = distance of the load on the fulcrum E = elasticity coefficient w = amplitude of the crystal x = thickness of the crystal Suppose that L and E are equal for the raw material and the precipitated material. Additionally, suppose that w / w0 = x / x0 = 1 0. Then, (eL) o = 6P0L / (Ew0Xo2) >; where the subscript '0' refers to raw material e = 6PL / (Ewx2), for the microprecipitate Equation (eL) hey, 6PL / (Ewx2) = 6P0L / (Ew0xo2) After simplification, P = Po (w / w0) (x / xo) 2 = P0 (0.1) (0.1) 2 = 0.001 P0 In this way, the yield strength, P, required to break the microprecipitated solid is one thousandth of the required force required to break the crystalline solid Of start. If, due to rapid precipitation, grid defects or amorphic properties are introduced, then the coefficient € should decrease, making the microprecipitate even easier to dissociate.

Example 9: Preparation of prednisolone suspension at 1.6% (w / v) with 0.05% sodium deoxycholate and 3% N-methyl-2-pyrrolidinone Process Category 3, Method B A process curve is presented of total manufacture in FIG. 8. A concentrated solution of prednisolone and sodium deoxycholate was prepared. Prednisolone (32 g) and sodium deoxycholate (1 g) were added to a sufficient volume of 1-methyl-2-pyrrolidinone (NMP) to produce a final volume of 60 mL. The resulting prednisolone concentration was approximately 533.3 mg / mL and the concentration of sodium deoxycholate was approximately 16.67 mg / mL. 60 mL of N MP concentrate was added to 2 L of water cooled at 5 ° C at an addition rate of 2.5 mL / min while stirring at approximately 400 rpm. The resulting suspension contained crystals in the form of thin needles less than 2 μm in amplitude (FIG 9). The concentration contained in the precipitated suspension was prednisolone at 1.6% (w / v), sodium deoxycholate at 0.05% and NMP at 3%. The precipitated suspension was adjusted to pH 7.5-8.5 by the use of sodium hydroxide and hydrochloric acid, after homogenizing (homogenizer by Avestin C-50 piston interval) for 10 passes at 10,000 psi. The NMP was removed by performing 2 successive centrifugation steps that replaced the supernatant each time with a fresh solution of surfactant, which contained the desired concentrations of surfactants needed to stabilize the suspension (see Table 2). The suspension was homogenized for another 10 passes at 10,000 psi. The final suspension contained particles with an average particle size of less than 1 μm and 99% particles smaller than 2 μm. FIG. 10 is a photomicrograph of the final prednisolone suspension after homogenization. A variety of surfactants other than variant cohcentrations were used in the centrifugation / surfactant replacement stage (see Table 2). Table 2 lists combinations of surfactants that were stable with respect to particle size (mean <1 μm, 99% < 2 μm), pH (6-8), drug concentration (less than 2% loss) and Re-suspension capacity (resuspended in 60 seconds or less). Notably, this process allows the addition of the active compound to an aqueous diluent without the presence of a surfactant or other additive. This is a modification of the method of Method B in FIG. 2.

Table 2: List of stable prednisolone suspensions, prepared by micro-rection procedure of FIG. 8 (For example 9 Difference in concentration of traconazole between samples stored during 2 months at 5 and 25 ° C ** Stable through at least 6 months Particle sizes (by diffusion of light by laser), in microns: 5 ° C: 0.80 ( media), 1 .7 (99%) 25 ° C: 0.90 (average); 2.51 (99%) 40 ° C: 0.99 (average); 2.03 (99%) Difference in the concentration of itraconazole between samples stored at 5 and 25 ° C: < 2% Example 10: Preparation of prednisolone suspension by use of Process Category 3, Method A with homogenization 32 g of prednisolone was dissolved in 40 mL of NMP. Soft heating was required at 40-50 ° C to effect the dissolution. The drug NMP concentrate was subsequently dripped at 2.5 mL / min in 2 liters of a stirred solution consisting of 0.1.2% lecithin and 2.2% glycerin. No other surface modifiers were added. The surfactant system was regulated at pH = 8.0 with 5 mM regulator tris and the temperature was maintained at 0o to 5o during the entire precipitation process. The post-precipitated dispersion was cooled after homogenizing (5-15 ° C) for 20 passes at 10,000 psi. After homogenization, the NMP was removed by centrifugation of the suspension, removing the supernatant and replacing the supernatant with fresh surfactant solution. This post-centrifuged suspension was cooled re-homogenized (5-1 5 ° C) for another 20 passes at 10,000 psi. The particles produced by this process have a mean diameter of 0.927 μm with 99% of the particles being less than 2.36 μm.

Example 1 1: Preparation of nabumetone suspension by use of Process Category 3, Method B with homogenization The surfactant (2.2 g of poloxamer 1 88) was dissolved in 6 mL of N-methyl-2-pyrrolidinone. This solution was stirred at 45 ° C for 15 minutes, after which 1 .0 g of nabumetone was added. The drug dissolved rapidly. The diluent was prepared, which consisted of 5 mM of tris regulator with 2.2% glycerol and was adjusted to pH 8. A portion of 100 mL diluent was cooled in an ice bath. The drug concentrate was added slowly (approximately 0.8 mL / min) to the diluent with vigorous stirring. These crude suspension was homogenized at 15,000 psi for 30 minutes and then at 20,000 psi for 30 minutes (temperature = 5 ° C). The final nanosuspension was found to be 930 nm in effective average diameter (analyzed by laser diffraction). 99% of the particles were less than about 2.6 microns.

Example 12: Preparation of nabumetone suspension by use of Process Category 3, Method B with homogenization and the use of Solutol® HS 15 as the surfactant. Replacement of the supernatant with a phospholipid medium Nabumetone (0.987 grams) was dissolved in 8 mL of N-methyl-2-pyrrolidinone. To this solution was added 2.2 grams of Solutol® HS 15. This mixture was stirred until complete dissolution of the surfactant in the drug concentrate. The diluent was prepared, which consisted of 5 mM of tris regulator with 2.2% glycerol and which adjusted the pH to 8. The diluent was cooled in an ice bath, and the drug concentrate was slowly added (approximately 0.5 mL / min) to the diluent with vigorous stirring. This crude suspension was homogenized for 20 minutes at 15,000 psi, and for 30 minutes at 20,000 psi. The suspension was centrifuged at 15,000 rpm for 15 minutes and the supernatant was removed and discarded. The remaining solid granule was re-suspended in a diluent consisting of 1.2% phospholipids. This medium was equal in volume to the amount of supernatant removed in the previous step. The resulting suspension was then homogenized at approximately 21,000 psi for 30 minutes. The final suspension was analyzed by laser diffraction and found to contain particles with an average diameter of 542 nm, and a 99% cumulative particle distribution, sized to less than 1 micron.

Example 13: Preparation of 1% itraconazole suspension with poloxamer with particles of an average diameter of approximately 220 nm. Traconazole concentrate was prepared by dissolving 1 0.02 grams of itraconazole in 60 mL of N-methyl-2-pyrrolidinone. Heating at 70 ° C was required to dissolve the drug. The solution was then cooled to room temperature.

A 50 mM portion of a tris (hydroxymethyl) aminomethane regulator (tris buffer) was prepared and the pH was adjusted to 8.0 with 5M hydrochloric acid. An aqueous surfactant solution was prepared by combining 22 g / L of poloxamer 407, 3.0 g / L of egg phosphatides, 22 g / L of glycerol and 3.0 g / L of sodium cholate dihydrate. 900 mL of the surfactant solution was mixed with 1 00 mL of the tris buffer to provide 1000 mL of aqueous diluent. The aqueous diluent was added to the homogenizer hopper (APV Gaulin Model 15MR-8TA), which was cooled by using an ice jacket. The solution was stirred rapidly (4700 rpm) and the temperature was monitored. The itraconazole concentrate was added slowly, by use of a syringe pump, at a rate of approximately 2 mL / min. The addition was completed after approximately 30 minutes. The resulting suspension was stirred for another 30 minutes while the hopper was still cooled in an ice jacket and an aliquot was removed for light microscopy analysis of any dynamic light diffusion. The remaining suspension was subsequently homogenized for 15 minutes at 10,000 psi. At the end of the homogenization, the temperature had risen to 74 ° C. The homogenized suspension was collected in a 1 L Type I glass bottle and sealed with a rubber seal. The bottle containing the suspension was stored in a refrigerator at 5 ° C. A sample of the suspension before homogenization showed that the sample consists of both free particles, groups of particles and multilamellar lipid bodies. Free particles may not be clearly visualized due to Brownian movement; however, many of the aggregates appeared to consist of non-crystalline, amorphous material. The homogenized sample contained free submicron particles that have excellent size homogeneity without visible lipid vesicles. The diffusion of dynamic light showed a monodisperse logarithmic size distribution with an average diameter of approximately 220 nm. The upper 99% cumulative size cut was approximately 500 nm. FIG. 1 1 shows a comparison of the size distribution of the prepared nanosuspension with that of a typical parenteral fat emulsion product (10% Intralipid®, Pharmacia).

Example 14: Preparation of nanosuspension of 1% itraconazole with hydroxyethylstarch Preparation of Solution A: Hydroxyethyl starch (1 g, Ajinomoto) was dissolved in 3 mL of N-methyl-2-pyrrolidinone (NMP). This solution was heated in a water bath at 70-80 ° C for 1 hour. In another container, 1 g of itraconazole (Wyckoff) was added. Three mL of NMP was added and the mixture was heated to 70-80 ° C to effect the dissolution (approximately 30 minutes). The phospholipid (Lipoid S-1 00) was added to this hot solution. Heating continued at 70-90 ° C for 30 minutes until all the phospholipid was dissolved. The hydroethyl starch solution was combined with the itraconazole / phospho-lipid solution. The mixture was heated for another 30 minutes at 80-95 ° C to dissolve the mixture. Addition of Solution A to Tris Regulator: Ninety-four (94) mL of 50 mM regulator tris (hydroxylethyl) aminomethane was cooled in an ice bath. As the tris solution was rapidly emptied, hot Solution A (see above) was slowly added dropwise (less than 2 cc / minute). After complete addition, the resulting suspension was sonic (Cole-Parmer Ultrasonic Processor - 20,000 Hz, 80% amplitude parameter) while still cooling in the ice bath. A one-inch solid probe was used. The sonication was continued for 5 minutes. The ice bath was removed, the probe was removed and re-tuned, and the probe was again immersed in the suspension. The suspension is sonicated again for another 5 minutes without the ice bath. The sonicator was withdrawn once more and re-tuned, and after the immersion of the probe, the sample was sonicated for another 5 minutes. At this point, the temperature of the suspension had risen to 82 ° C. The suspension was rapidly cooled again in an ice bath and, when it was found below room temperature, it was emptied into a Type I glass bottle and sealed. Microscopic visualization of the particles indicated individual particle sizes of the order of one micron or less. After one year of storage at room temperature, the suspension was re-evaluated with respect to. particle size and it was found to have a mean diameter of approximately 300 nm.

Example 15: Prophetic Example of Method A using HES The present invention contemplates the preparation of a nanosuspension of 1% itraconazole with hydroxyethylstarch using Method A following the steps of Example 14 except that HES would be added to the buffer solution of tris in place of the NMP solution. The aqueous solution may have to be heated to dissolve the HES.

Example 16: Seeding during Homogenization to Convert a Mixture of Polymorphs into the More Stable Polymorph Preparation of the Sample. A nanosuspension of itraconazole was prepared by a microprecipitation-homogenization method, as follows. Itraconazole (3 g) and Solutol HR (2.25 g) were dissolved in 36 mL of N-methyl-2-pyrrolidinone (NMP) with low heat and agitation to form a drug concentrate solution. The solution was cooled to room temperature and filtered through a 0.2 μm nylon filter under vacuum to remove undissolved drug or particulate matter. The solution was observed under polarized light to ensure that no crystalline material was present after filtration. The drug concentrate solution was then added at 1.0 mL / minute to approximately 264 mL of an aqueous buffer solution (22 g / L glycerol in 5 mM tris buffer). The aqueous solution was maintained at 2-3 ° C and was continuously stirred at approximately 400 rpm during the addition of drug concentrate. Approximately 100 mL of the resulting suspension was centrifuged and the solids re-suspended in a pre-filtered solution of 20% NMP in water. This suspension was re-centrifuged and the solids were transferred to a vacuum oven overnight, drying at 25 ° C. The resulting solid sample was labeled SMP 2 PRE. Characterization of the Sample. The SMP 2 PRE sample and the itraconazole sample of raw material were analyzed by the use of powder x-ray diffractometry. The measurements were carried out by using a Rigaku Min¡Flex + instrument with copper radiation, a stage size of 0.02 ° 22 and scanning speed of 0.25 ° 22 / minute. The resulting powder diffraction patterns are shown in FIG. 12. The patterns show that SMP-2-PRE is significantly different from the raw material, suggesting the presence of a different polymorph or pseudopolymorph. The differential scanning calorimetry (DSC) traces for the samples are shown in FIGS. 13a and b. Both samples are heated at 2 ° / min to 1 80 ° C in hermetically sealed aluminum troughs. The itraconazole trace of raw material (Fig. 13a) shows a tapered endotherm at approximately 165 ° C. The trace for SMP 2 PRE (FIG.13b) exhibits two endotherms at approximately 1 59 ° C and 153 ° C. This result, in combination with powder X-ray diffraction patterns, suggests that SMP 2 PRE consists of a mixture of polymorphs, and that the predominant form is a polymorph that is less stable than the polymorph present in the raw material. Additional evidence for this conclusion is provided by the DSC trace in FIG. 14, which shows that after heating AMP 2 PRE through the first transition, after cooling and re-heating, the less stable polymorph fuses and re-crystallizes to form the more stable polymorph. Sowing. A suspension was prepared by combining 0.2 g of solid SMP 2 PRE and 0.2 g of itraconazole from raw material with distilled water to a final volume of 20 mL (seeded sample). The suspension was stirred until all solids were wetted. A second suspension was prepared in the same manner but without adding itraconazole from raw material (unseeded sample). Both suspensions were homogenized at approximately 18,000 psi for 30 minutes. The final temperature of the suspensions after homogenization was approximately 30 ° C. The suspensions were then centrifuged and the solids were dried for about 16 hours at 30 ° C. FIG. 15 shows the DSC traces of the sown and unseeded samples. The heating rate for both samples was 2 ° / min to 1 80 ° C in hermetically sealed aluminum troughs. The trace of the unseeded sample shows two endotherms, indicating that the polymorph mixture still occurs after homogenization. The trace for the sown sample shows that the sowing and homogenization originate the conversion of the solids into the stable polymorph. Therefore, the plant seems to have an influence on the kinetics of the transition from the less stable to the more stable polymorphic form.

Example 17: Sow during Precipitation to Preferably Form a Stable Polymorph. Preparation of the Sample. A concentrate of Traconazole-NMP drug by dissolving 1.67 g of itraconazole in 10 mL of NMP with shaking and gentle heating. The solution was filtered twice by the use of 0.2 μm syringe filters. The itraconazole nanosuspensions were then prepared by the addition of 1.2 mL of the drug concentrate to 20 L of an aqueous receptor solution at about 3 ° C and stirring at about 3 ° C and stirring at about 500 rpm. A nanosuspension was prepared by using a mixture of approximately 0.02 g of itraconazole from raw material in distilled water as the receiving solution. An unplanted nanosuspension was prepared by using distilled water only as the receiving solution. Both suspensions were centrifuged, the supernatants were decanted and the solids were dried in a vacuum oven at 30 ° C for about 16 hours.

Characterization of the sample. FIG. 16 shows a comparison of the DSC traces for the solids from the sown and unseeded suspensions. The samples were heated at 2 ° / min to 1 80 ° C in hermetically sealed aluminum troughs. The dotted line represents the unseeded sample, which shows two endotherms, indicating the presence of a polymorphic mixture. The solid line represents the sown sample, which only shows an endotherm near the expected melting temperature of the raw material, indicating that the seeded material induced the exclusive formation of the more stable polymorph.

Example 1 8: Polymorphous Control by Sowing the Drug Concentrate Preparation of the Sample. The solubility of itraconazole in NMP at room temperature (approximately 22 ° C) was determined experimentally at 0.16 g / mL. A suspension of 0.20 g / mL of drug concentrate was prepared by dissolving 2.0 g of itraconazole and 0.2 g of Poloxamer 188 in 10 mL of NMP with heat and agitation. This solution was then allowed to cool to room temperature to produce a supersaturated solution. A microprecipitation experiment was then carried out immediately in which 1.5 mL of the drug concentrate was added to 30 mL of an aqueous solution containing 0.1% deoxycholate, 2.2% glycerol. The aqueous solution was maintained at ~ 2 ° C and a stirring speed of 350 rpm during the addition step. The resulting pre-suspension was homogenized at -13,000 psi for approximately 10 minutes at 50 ° C. The suspension was then centrifuged, the supernatant was decanted and the solid crystals were dried in a vacuum oven at 30 ° C for 135 hours. The supersaturated drug concentrate was subsequently matured by storage at room temperature in order to induce crystallization. After 12 days. The drug concentrate darkened, indicating that crystal formation had occurred. A suspension of itraconazole was prepared from the drug concentrate, in the same manner as in the first experiment, by adding 1.5 mL to 30 mL of an aqueous solution containing 0.1% deoxycholate, 2.2% glycerol. The aqueous solution was maintained at ~ 5 ° C and a stirring speed of 350 rpm during the addition step. The resulting pre-suspension was homogenized at ~1 3,000 psi for approximately 10 minutes at 50 ° C. The suspension was then centrifuged, the supernatant was decanted and the solid crystals were dried in a vacuum oven at 30 ° C for 135 hours. Characterization of the Sample. X-ray powder diffraction analysis was used to determine the morphology of the dried crystals. The resulting patterns are shown in FIG. 17. The crystals of the first experiment (using fresh drug concentrate) were determined to consist of the more stable polymorph. In contrast, the crystals of the second experiment (matured drug concentrate) were composed predominantly of the less stable polymorph, with a small amount of the more stable polymorph also present. Accordingly, it is believed that maturation induced crystal formation of the less stable polymorph in the drug concentrate, which then acts as the seed material during the microprecipitation and homogenization steps, so that the polymorph is preferably formed less stable.

Example 19: Continuous Solvent Removal Process by Cross Flow Ultrafiltration FIG. 20 is a schematic diagram illustrating a continuous process of solvent removal by cross-flow filtration for the production of an aqueous suspension of small particles of itraconazole, which is essentially solvent-free. A solution of 20 g of itraconazole in 120 mL of NMP was mixed with a surfactant solution containing 24 g of phospholipids and 44 g of glycerin in 2 L of WFI to form a mixture to initiate the microprecipitation process. The mixture was then introduced into the homogenizer in which the mixture was homogenized. After homogenization, the mixture was transferred to a feed tank. An additional 4.5 L of WFI was also added to the feed tank to rinse the mixture. The rinsed mixture then underwent an ultrafiltration process three times, in which the retentate, consisting of the aqueous suspension of the particles, was recycled to the feed tank while the infiltrate was removed and analyzed for NMP. The process also included an additional step of rinsing the solvent-free aqueous suspension with 1 L of replacement surfactant solution containing 12 g of phospholipids, 22 g of glycerin and 1.42 g of sodium phosphate. The small particles in the replacement surfactant solution were subsequently homogenized.

Example 20: Continuous Solvent Removal Process by Flow Crossing Ultrafiltrate I including Concentration Step A The process described in Example 19 included an additional concentration step of the rinsed batch, which is from 10 L to 2 L in this example , before experiencing diafiltration for 10 rinse cycles. This method is particularly suitable for organic compounds having limited aqueous solubility.

Example 21: Removal of NMP on Process Ascending Scale The continuous process of solvent removal, as described in Example 1 9, can be scaled from a batch of 200 mL to a batch of 10 L, and NMP levels after solvent removal for each batch are shown in FIG. twenty-one .

Example 22: Removal of NMP to Different Scales, for Two Different Drugs and Different Surfactants The process described in Example 19 was also applied at different scales, for itraconazole and budesonide with two different surfactants. The levels of residual NMP in the aqueous suspension are summarized in Table 3.

Table 3: Withdrawal of MPN achieved at different scales, for two different drugs, two different surfactants Example 23: Mass Balance for NMP and Drug Potency in Diverse Lots with Different Scales The mass balance was calculated for various batches of samples from the continuous solvent removal process, as described in Example 19 at different scales. In four batches of 10 L at the pilot scale, 83% NMP was added. In two laboratory-scale batches of 200 mL, 79% NMP was added. The non-added NMP was potentially adsorbed to the ultrafiltration membrane, pipe and / or particles. More than 95% drug potency was maintained during the 10 L batches while 70% drug potency was retained for the 200 L batches. The loss of drug potency was probably due to transfer operations.

Example 24: Combined and Continuous Process for the Production of Peel Particles In the combined and continuous process, the drug concentrate containing a drug dissolved in the water-miscible solvent and the second aqueous solvent (the anti-solvent) are mixed online in the homogenization container. The homogenization and ultrafiltration of the cross flow are carried out simultaneously with the mixture circulating in a closed cycle of the homogenizer to the ultrafiltration unit and then back to the homogenizer. The circulation is repeated as many cycles as necessary in order to remove the organic solvent to the desired level. The process is illustrated schematically in FIG. 22 Example 25: Combined and Continuous Process for the Production of Itraconazole Peel Particles Precipitated in a Poloxamer Aqueous Medium 188 A solution of itraconazole in NMP was precipitated in a solution of aqueous surfactant containing 0.1% poloxamer 188, 0.1% deoxycholate and 2.2% glycerin. High pressure homogenization and solvent removal were initiated after the start of microprecipitation and continued until the end of microprecipitation. The final average particle size was 340 nm and no aggregate formation was observed under a microscope. The level of residual NMP was less than 10 ppm. The whole process was conducted in two hours, which represents a 50% reduction in processing time compared to a similar batch made by the use of microprecipitation, followed by homogenization, followed by centrifugation, followed by homogenization. Although specific embodiments have been illustrated and described, numerous modifications come to mind without departing from the spirit and scope of the invention and the scope of protection is limited only by the scope of the accompanying claims.

Claims (46)

1. REIVI NDICATIONS 1. A method for preparing small particles of an organic compound, the solubility of which is greater in a water-miscible first solvent than in a second solvent that is aqueous, characterized in that it comprises: (i) dissolving the organic compound in the first solvent miscible in water to form a solution; (ii) mixing the solution with the second solvent to form a mixture; and (iii) simultaneously homogenizing the mixture and continuously removing the first solvent from the mixture so as to form an aqueous suspension of small particles having an average effective particle size of less than about 1000 μm where the suspension aqueous is essentially free of the first solvent. The method according to claim 1, characterized in that the first solvent miscible in water is a protic organic solvent. The method according to claim 2, characterized in that the protic organic solvent is selected from the group consisting of alcohols, amines, oximes, hydroxamic acids, carboxylic acids, sulfonic acids, phosphonic acids, phosphoric acids, amides and ureas. 4. The method according to claim 1, characterized in that the first solvent miscible in water is an aprotic organic solvent. 5. The method according to claim 4, characterized in that the aprotic organic solvent is a dipolar aprotic solvent. The method according to claim 5, characterized in that the dipolar aprotic solvent is selected from the group consisting of: fully substituted amides, fully substituted ureas, ethers, cyclic ethers, nitrile, ketones, sulphones, sulfoxides, completely substituted phosphates, Phosphonate esters, phosphoramides, and nitro compounds. 7. The method according to claim 1, characterized in that the first solvent miscible in water is selected from the group consisting of: N-methyl-2-pyrrolidinone (N-methyl-2-pyrrolidone), 2-pyrrolidinone (2) -pyrrolidone), 1,3-dimethyl-2-imidazolidinone (DMI), dimethyl sulfoxide, dimethylacetamide, acetic acid, lactic acid, methanol, ethanol, isopropanol, 3-pentanol, n-propanol, benzyl alcohol, glycerol, butylene glycol ( butanediol), ethylene glycol, propylene glycol, mono- and diacylated monoglycerides, glyceryl caprylate, dimethyl isosorbide, acetone, dimethylsulfone, dimethylformamide, 1,4-dioxane, tetramethylenesulfone (sulfolane), acetonitrile, nitromethane, tetramethylurea, hexamethylphosphoramide ( HMPA), tetrahydrofuran (THF), dioxane, diethyl ether, tert-butylmethyl ether (TBME), aromatic hydrocarbons, alkenes, alkanes, halogenated aromatics, halogenated alkenes, halogenated alkanes, xylene, toluene, benzene, substituted benzene, ethyl acetate , methyl acetate, butyl acetate, chlorobenzene, bromobenzene, chlorotoluene, trichloroethane, methylene chloride, ethylenedichloride (EDC), hexane, neopentane, heptane, isooctane, cyclohexane, polyethylene glycol (PEG), PEG-4, PEG-8 , PEG-9, PEG-12, PEG-14, PEG-16, PEG-120, PEG-75, PEG-1 50), polyethylene glycol esters, PEG-4 dilaurate, PEG-20 dilaurate, PEG isostearate -6, PEG-8 palmito-stearate, PEG-1 palmito-stearate 50, polyethylene glycol sorbitan, sorbitan isostearate PEG-20, polyethylene glycol monoalkyl ethers, PEG-3 dimethyl ether, PEG-4 dimethyl ether, polypropylene glycol (PPG), polypropylene alginate, PPG-1 butanediol 0, PPG-1 0 methyl glucose ether, PPG-20 methyl glucose ether, PPG-15 stearyl ether, propylene glycol dicaprylate / dicaprate, propylene glycol laurate, and glycofurol (polyethylene glycol ether of tetrahydrofurfuryl alcohol). The composition according to claim 1, characterized in that the first water-miscible solvent is N-methyl-2-pyrrolidinone. 9. The composition according to claim 1, characterized in that the first solvent miscible in water is lactic acid. 10. The method according to claim 1, characterized in that it further comprises mixing in the first water-miscible solvent or the second solvent or both, the first water-miscible solvent and the second solvent, of one or more surface modifiers selected from the group consisting of: anionic surfactants, cationic surfactants, non-ionic surfactants and biological modifiers active on the surface. eleven . The method according to claim 1, characterized in that the removal of the first solvent is by filtration. The method according to claim 1, characterized in that the filtration is flow cross ultrafiltration. The method according to claim 1 2, characterized in that the ultrafiltration comprises the concentration of the mixture to form a concentrate and diafiltrate the concentrate to remove the first solvent. The method according to claim 1, characterized in that a polymer membrane filter is used for ultrafiltration. The method according to claim 1, characterized in that a ceramic membrane filter is used for ultrafiltration. The method according to claim 1, characterized in that the first solvent is present in the aqueous suspension at less than about 100 ppm. The method according to claim 1, characterized in that the first solvent is present in the aqueous suspension at less than about 50 ppm. 18. The method according to claim 1, characterized in that the first solvent is present in the aqueous suspension at less than about 10 ppm. 9. The method according to claim 1, characterized in that the organic compound is sparingly soluble in water. The method according to claim 1, characterized in that the organic compound has a solubility in water of less than about 10 mg / mL. twenty-one . The method according to claim 1, characterized in that the organic compound is a pharmaceutically active compound. 22. The method according to claim 21, characterized in that the pharmaceutically active compound is itraconazole. 23. The method according to claim 21, characterized in that the pharmaceutically active compound is budesonide. 24. The composition according to claim 21, characterized in that the pharmaceutically active agent is carbamazepine. 25. The composition according to claim 21, characterized in that the pharmaceutically active agent is prednisolone. 26. The composition according to claim 21, characterized in that the pharmaceutically active agent is nabumetone. The method according to claim 1, characterized in that the small particles have an average effective particle size of from about 20 μm to about 10 nm. The method according to claim 1, characterized in that the small particles have an average effective particle size of from about 10 μm to about 10 nm. 29. The method according to claim 1, characterized in that the small particles have an average effective particle size of from about 2 μm to about 10 nm. 30. The method according to claim 1, characterized in that the small particles have an average effective particle size of from about 1 μm to about 10 nm. 31 The method according to claim 1, characterized in that the small particles have an average effective particle size of from about 400 nm to about 50 nm. 32. The method according to claim 1, characterized in that the small particles have an average effective particle size of from about 200 nm to about 50 nm. 33. The method according to claim 1, characterized in that it further comprises sterilizing the aqueous suspension. The method according to claim 33, characterized in that the sterilization of the aqueous suspension comprises the sterile filtration of the solution and the second solvent before mixing and carrying out the subsequent steps under aseptic conditions. 35. The composition according to claim 33, characterized in that the sterilization comprises thermal sterilization. 36. The method according to claim 35, characterized in that the thermal sterilization is carried out inside the homogenizer in which the homogenizer serves as a source of heating and pressurization for sterilization. 37. The method according to claim 33, characterized in that the sterilization comprises gamma radiation. 38. The method according to claim 1, characterized in that it further comprises removing the aqueous phase from the aqueous suspension in order to form a dry powder of the small particles. 39. The method according to claim 38, characterized in that the removal of the aqueous phase is selected from the group consisting of: evaporation, rotary evaporation, lyophilization, spray drying, diafiltration, centrifugation, force field fractionation, filtration high pressure and reverse osmosis. 40. The method according to claim 38, characterized in that it also comprises the step of adding a diluent to the small particles. 41 The method according to claim 40, characterized in that the diluent is suitable for parenteral administration of the particles. 42. A composition of small particles, prepared by the method according to claim 1. 43. The composition according to claim 42, characterized in that it is administered to a subject in need of the composition by a route selected from the group consisting of: parenteral, oral, pulmonary, topical, ophthalmic, nasal, buccal, rectal, vaginal , and transdermal. 44. The method according to claim 1, characterized in that the solution and the second solvent are mixed while the mixture is homogenized simultaneously and the first solvent is continuously removed from the mixture. 45. A method for the preparation of small particles of an organic compound, the solubility of which is greater in a water-miscible first solvent than in a second solvent that is aqueous, characterized in that it comprises: (i) dissolving the organic compound in the first solvent miscible in water to form a solution; (ii) mixing the solution with the second solvent to form a mixture; and (ii) simultaneously homogenizing the mixture and continuously removing the first solvent from the mixture by cross-flow ultrafiltration so as to form an aqueous suspension of small particles having an average effective particle size of less than about 100 μm where the aqueous suspension is essentially free of the first solvent. 46. A method for the preparation of small particles of an organic compound, the solubility of which is greater in a water-miscible first solvent than in a second solvent that is aqueous, characterized in the method because it comprises: (i) dissolving the organic compound in the first solvent miscible in water to form a solution; and (ii) simultaneously mixing the solution with the second solvent so as to form a mixture while the mixture is homogenized and the first solvent is continuously removed from the mixture in order to form an aqueous suspension of small particles having a size of effective average particle of less than about 100 μm wherein the aqueous suspension is essentially free of the first solvent.