RU2181054C2 - Microemulsion preconcentrate - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: means has hardly soluble agent and carrier agent having hydrophilic phase having dimethyl sorbide and/or lower alkyl-alcane ester, lipophilic phase and surfactant substance. Cyclosporin or macrolides are useable as active agent. EFFECT: enhanced effectiveness of treatment; improved bioavailability properties. 5 cl, 5 dwg

Description

 The present invention relates to new galenic formulations, in particular new galenic formulations, in which the active ingredient is a sparingly soluble active agent, for example macrolide, or, in particular, a cyclic poly-N-methylated undecapeptide or peptolid of the cyclosporin class - see, for example, patent publications Great Britain 2222770 and 2257359 A and analogs.

 From these publications of British patents it is known that the use of cyclosporins causes highly specific difficulties with respect to their administration in general and galenic compositions in particular, for example, problems of stability, drug bioavailability and inconsistency of the reaction to the administered dose in one or in different patients.

 To overcome these and similar difficulties, British Patent Publications 2222770 and 2257359 A describe galenic formulations with cyclosporin as the active ingredient in the form of a microemulsion or microemulsion preconcentrate. Such formulations typically include 1) a hydrophilic phase, 2) a lipophilic phase, and 3) a surfactant.

 In accordance with the present invention, it was unexpectedly found that a particularly stable microemulsion or microemulsion preconcentrate of galenic formulations with sparingly soluble active agents having the most interesting bioavailability characteristics and a reduced dispersion in bioavailability parameters in both one and different subjects can be obtained using a hydrophilic phase comprising dimethyl isosorbide.

 It has been proposed [WO 94/05312] the use of dimethyl isosorbide to produce cyclosporin-containing formulations, but only in the form of complex formulations. The range of components of these considered formulations is precisely defined, therefore it is obvious that the authors of WO 94/05312 believed that only a limited number of dimethyl isosorbide-based formulations would be active. Thus, in Examples 1, 2 and 6, WO 94/05312 describes a composition containing dimethyl isosorbide with an emulsifier - anhydrous mannitol oleyl ether (Montanide 103), another emulsifier - citroglyceride (Axol C62), lipogel - aluminum-magnesium hydroxystearate (Gilugel MIG) short chain fatty acid glyceride (Miglyol 812) or milk thistle oil. Dimethyl isosorbide is described only as a solvent, and there is no indication that it can be used as a component of the hydrophilic phase of the microemulsion. The authors of WO 94/05312 were not able to reveal its capabilities in this regard.

 In accordance with the present invention, it was unexpectedly found that such microemulsion systems, contrary to the experience accumulated in this field, can actually be prepared in practice with the inclusion of dimethyl isosorbide as a component of the hydrophilic phase.

The present invention in one of its aspects encompasses a pharmaceutical composition comprising a microemulsion preconcentrate comprising a sparingly soluble active agent and a carrier comprising:
1) a hydrophilic phase, which includes dimethyl isosorbide and / or lower alkyl alkane ether;
2) lipophilic phase;
3) surfactant.

 Preferred is a composition in the form of a “microemulsion preconcentrate” of a type which provides m / v (oil-in-water) type microemulsions. However, the composition may exist in the form of a microemulsion, which further comprises an aqueous phase, preferably water.

 A “microemulsion preconcentrate” as defined herein is a composition that spontaneously forms a microemulsion in an aqueous medium, such as water, when diluted, for example, from 1: 1 to 1:10, or in gastric juice after oral administration.

Как правило, микроэмульсии содержат капельки или частицы, имеющие среднее значение диаметра менее чем приблизительно 1500

обычно менее 100 нм, как правило более 10 нм, и стабильны свыше 24 часов. Дополнительные характеристики можно найти в вышеупомянутой заявке на патент Великобритании 2222770.A “microemulsion” is a transparent or substantially transparent colloidal dispersed system that forms spontaneously or mainly spontaneously when its components are brought into contact. The microemulsion is thermodynamically stable and contains dispersed particles of a size of less than approximately 2000

Typically, microemulsions contain droplets or particles having an average diameter value of less than about 1500

typically less than 100 nm, typically more than 10 nm, and stable over 24 hours. Additional characteristics can be found in the aforementioned UK patent application 2222770.

 The specified lipophilic phase may contain from 5 to 85 weight% of the carrier, for example from 10 to 85%; preferably from 15 to 70 weight%, more preferably from 20 to 60 weight%, and even more preferably about 25 weight%.

 The specified surfactant may contain from 5 to 80 weight% of the carrier; preferably from 10 to 70 weight%, more preferably from 20 to 60 weight%, and even more preferably about 40 weight%.

 The specified hydrophilic phase may contain from 5 to 50 weight% of the carrier, for example from 10 to 50%; preferably from 15 to 40 weight%, more preferably from 20 to 35 weight%.

 The specified active agent may be present in a weight amount of up to about 20% by weight of the composition. The specified active agent is preferably presented in an amount of from 1 to 15% by weight of the composition, for example from about 2 to 10%.

Preferably, when said sparingly soluble active agent is a lipophilic drug, for example cyclosporin or macrolide. As used herein, the term "sparingly soluble" is understood in the sense that the solubility in water at 20 ^{° C.} is less than 0.01% w / v.

Cyclosporins to which the present invention is applicable have pharmaceutical uses, for example, as immunosuppressants, antiparasitic agents and multidrug resistance reversers, they are known in the art, in particular cyclosporin A (also known as Ciclosporin hereinafter); cyclosporin G, [O- (2-hydroxyethyl) - (D) Ser] ⁸ -Ciclosporin; and [3'-dehydroxy-3'-keto MeBmt] ¹ - [Val] ² -Ciclosporin. Ciclosporin is preferred.

 As used herein, the term “macrolide” refers to a macrocyclic lactone, for example, a compound having a 12-membered or multiple-member lactone ring. Of particular interest are “lactam macrolides,” that is, macrocyclic compounds having a lactam (amide) bond in the macrocycle in addition to the lactone (ether) bond, for example, lactam macrolides produced by microorganisms of the genus Streptomyces, namely rapamycin, ascomycin and FK506, and also their numerous derivatives and analogues. It has been shown that such lactam macrolides have interesting pharmaceutical properties, in particular immunosuppressive and anti-inflammatory.

[См. например, McAlpine, J.B., et al., J. Antibiotics (1991) 44: 688; Schreiber, S. L. , et al., J. Am. Chem. Soc. (1991) 113: 7433; патент США 3929992] . (Для рапамицина были преложены различные схемы нумерации. При указании названия специфических производных рапамицина во избежание путаницы данные названия приводятся со ссылкой на рапамицин с использованием схемы нумерации формулы А.) Рапамицин является очень сильным иммуносупрессором и, как было также показано, обладает противоопухолевой и антигрибной активностями. Однако его применение в качестве фармацевтического средства ограничивается его очень низкой и изменчивой биодоступностью, равно как и его высокой токсичностью. Кроме того, рапамицин очень плохо растворим, что затрудняет приготовление стабильных галеновых составов. Известны многочисленные производные рапамицина. Известны [WO 94/02136] некоторые 16-О-замещенные рапамицины. Известны 40-О-замещенные рапамицины [US 5258389 и WO 94/09010 (О-арил- и О-алкилрапамицин); WO 92/05179 (эфиры карбоновых кислот), US 5118677 (амидные эфиры), US 5118678 (карбаматы), US 5100883 (фторированные эфиры), US 5151413 (ацетали), US 5120842 (силиловые эфиры), WO 93/11130 (метиленрапамицин и производные), WO 94/02136 (метоксипроизводные), WO 94/02385 и WO 95/14023 (алкенильные производные)]. Известен [US 5256790] 32-О-дигидрорапамицин или замещенный рапамицин, например в US 5256790.Rapamycin is an immunosuppressive lactam macrolide that is produced by Streptomyces hygroscopicus. The structure of rapamycin is described [Kesseler, H., et al .; 1993; Helv. Chim. Acta; 76; 117]. The specified structure is described in formula A:

[Cm. for example, McAlpine, JB, et al., J. Antibiotics (1991) 44: 688; Schreiber, SL, et al., J. Am. Chem. Soc. (1991) 113: 7433; US patent 3929992]. (Various numbering schemes were proposed for rapamycin. When specifying the names of specific rapamycin derivatives to avoid confusion, these names are cited with reference to rapamycin using the numbering scheme of formula A.) Rapamycin is a very strong immunosuppressant and has also been shown to have antitumor and antifungal activities . However, its use as a pharmaceutical is limited by its very low and variable bioavailability, as well as its high toxicity. In addition, rapamycin is very poorly soluble, which makes it difficult to prepare stable galenic formulations. Numerous rapamycin derivatives are known. Some 16-O-substituted rapamycins are known [WO 94/02136]. 40-O-substituted rapamycins are known [US 5258389 and WO 94/09010 (O-aryl- and O-alkylrapamycin); WO 92/05179 (carboxylic acid esters), US 5118677 (amide esters), US 5118678 (carbamates), US 5100883 (fluorinated esters), US 5151413 (acetals), US 5120842 (silyl ethers), WO 93/11130 (methylene rapamycin and derivatives), WO 94/02136 (methoxy derivatives), WO 94/02385 and WO 95/14023 (alkenyl derivatives)]. Known [US 5256790] 32-O-dihydrorapamycin or substituted rapamycin, for example in US 5256790.

 Rapamycin and its structurally similar analogues and derivatives are called by the general term “rapamycins”.

 Ascomycins, among which the best known are FK506 and ascomycin, constitute another class of lactam macrolides, many of which have strong immunosuppressive and anti-inflammatory activity. FK506 is a lactam macrolide immunosuppressant produced by Streptomyces tsukubaensis 9993. The structure of FK506 is given in the Appendix to the 11th edition of the Merck Index (1989) in paragraph A5 (Merck Index). Ascomycin is described, for example, in US Pat. No. 3,244,492. A large number of derivatives of ascomycin and FK506 have been synthesized, including halogenated derivatives, such as 33-epichloro-33-deoxycoscomycin [EP 427680]. Ascomycin, FK506 and their structurally similar analogues and derivatives are referred to by the general term ascomycins.

Thus, the macrolide can be rapamycin or its O-substituted derivative, in which the hydroxyl group of the cyclohexyl ring of rapamycin is replaced by —OR ₁ , where R ₁ is hydroxyalkyl, hydroalkoxyalkyl, acylaminoalkyl and aminoalkyl; for example, 40-O- (2-hydroxy) ethylrapamycin, 40-O (3-hydroxy) propylrapamycin, 40-O- [2- (2-hydroxy) ethoxy] ethyl rapamycin and 40-O- (2-acetaminoethyl) rapamycin.

 A preferred compound is 40-O- (2-hydroxy) ethylrapamycin [WO 94/09010].

 Examples of compounds of class FK506 are the compounds mentioned above. These include, for example, FK506, ascomycin, and other naturally occurring compounds. In addition, they include synthetic analogues.

 A preferred compound of class FK506 is described [EP 427680, for example Example 66a], it is also known as 33-epichloro-33-deoxy-ascomycin. Other preferred compounds are also described [EP 465426 and EP 569337, for example the compound of Example 71 in EP 569337].

The hydrophilic phase component includes dimethyl isosorbide and / or lower alkyl alkane ether. The term lower alkyl is to be understood as encompassing alkyls containing a C ₁ to C ₄ chain, for example ethyl. The term alkane ester should be understood as including acetate and propionate. Ethyl acetate is preferred. The solubility of ethyl acetate in water at room temperature is 8.5 g per 100 ml. Preferably, the solubility of the lower alkyl alkane esters in water at room temperature is from about 1 to 30 g / 100 ml.

The hydrophilic phase may also include an additional component that can be selected from Transcutol (having the formula C ₂ H ₅ - [O (CH ₂ ) ₂ ] ₂ -OH), Glycofurol (also known as tetrahydrofurfuryl alcohol and polyethylene glycol ether) and 1,2 propylene glycol. The hydrophilic phase may include other hydrophilic additional components, for example lower alcohols such as ethanol. These additional components are usually introduced as partial substitutes for other components of the hydrophilic phase. Despite the fact that the use of ethanol in the compositions is not significant, it was found that it gives a particular advantage when it is necessary to prepare compositions in the form of capsules from soft gelatin. This is due to improved storage characteristics, in particular a decrease in the risk of precipitation of the active agent after encapsulation. Thus, storage stability can be improved by using ethanol or some other additional component as an additional ingredient in the hydrophilic phase. Ethanol may comprise from 0 to 60% by weight of the hydrophilic phase, preferably from 20 to 55% by weight, and more preferably from about 40 to 50% by weight. Small amounts of liquid polyethylene glycols may also be introduced into the hydrophilic phase.

Dimethyl isosorbide is also known as 3,6-dianhydro-2,5-diO-methyl-D-glucite. It is manufactured by ICI American Inc. under the trade name Arlasolve DMI. It has the following physicochemical properties:
Boiling Point - Approx. 234 ^o C
Density (25 ^o C) - 1,164
Refractive index - 1,467
Viscosity (25 ^o C) approx. - 5 MPa • s
Dielectric Constant - Approx. 7
It is known [GB 2222770] a wide variety of lipophilic phase components suitable for use in the present invention. Preferred components of the lipophilic phase are medium chain fatty acid triglycerides, mixed mono-, di-, triglycerides and transesterified ethoxylated vegetable oils.

The corresponding medium chain fatty acid triglycerides are known and are commercially available under the trade names Captex, Myritol, Capmul, Neobee and Mazol; most preferred is Miglyol 812. Miglyol 812 is a fractionated coconut oil containing capryl capric triglycerides with an approximate molecular weight of 520 daltons. Fatty acid composition: maximum C ₆ content of approximately 3%, C ₈ approximately 50 to 65%, C ₁₀ approximately 30 to 45%, maximum C ₁₂ content of 5%; the acid number is about 0.1; saponification number is approximately from 330 to 345; the maximum value of the iodine number is 1. Miglyol 812 is manufactured by Huels.

 These triglycerides are described [Fielder, H.P. "Lexikon der Hilfsstoffe fur Pharmazie, Kosmetik und angrenzende Gebiete", Editio Cantor, D-7960 Aulendorf, 3rd edition, revised and supplemented (1989)].

Mixed mono-, di-, and triglycerides preferably include mixtures of mono-, di- and triglycerides of C _12-20 fatty acids, mainly mixed mono-, di- and triglycerides of C _16-18 fatty acids. Fatty acids contained in mixed mono-, di- and triglycerides may include residues of both saturated and unsaturated fatty acids. Preferred, however, is the predominance of residues of unsaturated fatty acids, in particular residues of C ₁₈ fatty acids. It is acceptable that the mixed mono-, di- and triglycerides contain at least 60%, preferably at least 75%, more preferably at least 85% by weight of C ₁₈ mono-, di- and triglycerides of unsaturated fatty acids (e.g. linolenic, linoleic and oleic acids). It is also acceptable that the mixed mono-, di- and triglycerides contain less than 20%, for example from about 15% to 10% by weight or less of mono-, di- and triglycerides of saturated fatty acids (for example palmitic and stearic acids).

 Preferred is the predominance of mixed mono-, di- and triglycerides of mono- and diglycerides, for example when mono- and diglycerides comprise at least 50%, more preferably at least 70% of the total weight of the lipophilic phase. More preferred is a mono- and diglyceride content of at least 75% (e.g., approximately 80% or 85%) by weight of the lipophilic phase.

 Preferably, the monoglycerides comprise from about 25 to 50% based on the total weight of the lipophilic phase of all mixed mono-, di-, triglycerides. More preferred is a monoglyceride content of about 30 to 40% (e.g., 35 to 40%).

 Preferably, the diglycerides comprise from about 30 to 60% (based on the total weight of the lipophilic phase) of all mixed mono-, di-, triglycerides. More preferred is a diglyceride content of about 40 to 55% (e.g., 48 to 50%).

 Acceptable is the content of triglycerides in the composition of mixed mono-, di-, triglycerides, comprising at least 5%, but not more than approximately 25%, based on the total weight of the lipophilic phase. More preferred is a triglyceride content of about 7.5 to 15% (e.g., 9 to 12%).

 Mixed mono-, di-, and triglycerides can be obtained by mixing individual mono-, di-, or triglycerides in a specific ratio. Usually, however, they contain transesterification products of vegetable oils, for example almond, peanut, olive, peach, palm or preferably corn oil, sunflower oil or safflower oil, and most preferably corn oil, with glycerin.

 Such transesterification products can usually be obtained by known methods [GB 2257359 and / or WO 94/09211].

 In the case of the manufacture of soft gelatin capsules, it is preferable to first remove the glycerol residues to obtain a “substantially batch of product free of glycerin”.

 From the purified transesterification products of corn oil and glycerol, [GB 2257359 and / or WO 94/09211] the most suitable mixed mono-, di- and triglycerides, hereinafter referred to as “refined oil”, are obtained.

 Alternatively, the lipophilic phase may contain, for example, a pharmaceutically acceptable oil, preferably with an unsaturated component, for example vegetable oil or fish oil.

 Alternatively, the lipophilic phase may contain suitably transesterified ethoxylated vegetable oils, obtained, for example, from the interaction of various natural vegetable oils (e.g. corn, stone, almond, peanut, olive, soybean, sunflower oil, safflower oil, palm oil or mixtures thereof ) with polyethylene glycols with an average molecular weight of 200 to 800 in the presence of an appropriate catalyst. Such production methods are known in the art [see, for example, US Pat. No. 3,288,824]. Most preferred is a transesterified ethoxylated corn oil.

Transesterified ethoxylated vegetable oils are known and are commercially available under the trade name LABRAFIL (H. Fiedler, loc cit. Vol 2, page 707). Examples include LABRAFIL M 2125 CS (obtained from corn oil and having an acid value of less than 2, saponification number from 155 to 175, HLB (hydrophilic-lipophilic balance) value from 3 to 4, and iodine number from 90 to 100) and LABRAFIL M 1994 CS (obtained from stone oil and having an acid value of about 2, saponification number from 145 to 175, iodine number from 60 to 90). LABRAFIL M 2130 CS can also be used (which is a transesterification product of C _12-18 glyceride and polyethylene glycol, the melting point of which is approximately 35 to 40 ^° C, the acid number is less than 2, the saponification number is 185 to 200, and the iodine number is less than 3). A preferred transesterified ethoxylated vegetable oil is LABRAFIL M 2125 CS, which can be obtained, for example, from Gattefosse, Saint-Priest Cedex, France.

Examples of suitable surfactants for use in accordance with the present invention are:
i) reaction products of natural or hydrogenated castor oil and ethylene oxide. The reaction between natural or hydrogenated castor oil and ethylene oxide can be carried out with an approximate molar ratio of reactants from 1:35 to 1:60 and the possible removal of the polyethylene glycol component from the products. Similar diverse surfactants are commercially available. Polyethylene glycol hydrogenated castor oils commercially available under the trade name CREMOPHOR are particularly suitable. Most suitable are CREMOPHOR RH 40 having a saponification number of from about 50 to 60, an acid number of less than 1, a water content (Fischer) of less than 2%, an n _D ^{60 of} about 1.453 to 1.457, and an HLB of about 14 to 16; and CREMOPHOR RH 60, having a saponification number of from about 40 to 50, an acid number of less than 1, an approximate value of the iodine number of less than 1, a water content (Fischer) of about 4.5 to 5.5%, n _D ²⁵ values of from about 1.453 up to 1.457 and an HLB of about 15 to 17. A particularly preferred product of this class is CREMOPHOR RH 40. Polyethylene glycol castor oils, such as those sold under the trade name CREMOPHOR EL, having a molecular weight value (according to evaporative osmometry) equal to 1630, number about saponification from about 65 to 70, an acid number of about 2, an iodine number of from about 28 to 32 and an n _D ²⁵ value of about 1.471.

 Similar or identical products that can also be used are commercially available under the trade names NIKKOL (e.g. NIKKOL HCO-40 and HCO-60), MAPEG (e.g. MAPEG CO-40h), INCROCAS (e.g. INCROCAS 40) and TAGAT (e.g. polyoxyethylene glycerol esters and fatty acids, namely TAGAT RH 40; and TAGAT TO — polyoxyethylene glycerol trioleate having an HLB value of 11.3; TAGAT TO is preferred). A more detailed description of these surfactants can be found in Fiedler loc. cit.

ii) Esters of polyoxyethylene sorbitan and fatty acids, for example mono- and trilauryl, palmityl, stearyl and oleyl esters, known [Fielder, loc. cit., p. 1300-1304] and commercially available under the trade name TWEEN, including TWEEN products:
20 [polyoxyethylene (20) sorbitan monolaurate],
21 [polyoxyethylene (4) sorbitan monolaurate],
40 [polyoxyethylene (20) sorbitan monopalmitate],
60 [polyoxyethylene (20) sorbitan monostearate],
65 [polyoxyethylene (20) sorbitan tristearate],
80 [polyoxyethylene (20) sorbitan monooleate],
81 [polyoxyethylene (5) sorbitan monooleate],
85 [polyoxyethylene (20) sorbitan trioleate].

 Particularly preferred products of this class are TWEEN 40 and TWEEN 80.

iii) Fatty acid and polyoxyethylene esters, for example, stearic acid and polyoxyethylene esters, of the type known and commercially available under the trade name MYRJ [Fiedler, loc. cit. 2. sec 834-835]. A particularly preferred product of this class is MYRJ 52 having a D ²⁵ value of approximately 1.1, a melting point of approximately 40 to 44 ^{° C.} , an HLB value of approximately 16.9, an approximate acid value of 0 to 1, and a saponification number of 25 to 35.

iv) Polyoxyethylene-polyoxypropylene copolymers and block copolymers of the type known and commercially available under the trade names PLURONIC, EMKALYX and POLOXAMER (Fiedler, loc. cit., 2, p. 959). A particularly preferred product of this class is PLURONIC F68 having a melting point of about 52 ^° C and a molecular weight of from about 6800 to 8975). Another preferred product of this class is POLOXAMER 188.

 v) Dioctyl sulfosuccinate or di- [2-ethylhexyl] succinate [Fiedler, loc. cit., 1, p. 107-108].

 vi) Phospholipids, especially lecithins [Fiedler, loc. cit., 2, p. 943-944]. Suitable lecithins include, in particular, soya lecithins.

 vii) Mono- and diesters of fatty acids and propylene glycol, for example propylene glycol dicaprylate (also known and commercially available under the trade name MIGLYOL 840), propylene glycol dilaurate, propylene glycol hydroxy stearate, propylene glycol isostearate, propylene glycol glycol urate, propylene glycol glycol urate, etc. [Fiedler, loc. cit., 2, p. 808-809].

 Surfactants having a hydrophilic lipophilic balance (HLB) value of at least 10, for example Cremophor, are preferably selected.

(150 нм).Preferably, the relative ratio of the component (s) of the hydrophilic phase, lipophilic phase and surfactant lies within the microemulsion region in the standard ternary diagram. The compositions thus obtained are microemulsion preconcentrates of high stability, capable of forming microemulsions with an average particle size <1500 when added to water

(150 nm).

 These microemulsion preconcentrate formulations, for example those of the examples given below, can exhibit good stability indicators as identified in standard stability tests, for example, storage stability for up to one, two or three years or even more. The compositions of the microemulsion preconcentrates of this invention form microemulsions that are stable, for example, up to one day or more.

 The pharmaceutical composition may also include other additives or ingredients, for example antioxidants (such as ascorbyl palmitate, butyl hydroxyanisole (BHA), butyl hydroxytoluene (BHT) and tocopherols) and / or preservatives. These additives or ingredients are present in an amount of about 0.05 to 1% by weight of the total weight of the composition. The pharmaceutical composition may also contain sweeteners or flavorings in an amount up to about 2.5 or 5% by weight, relative to the total weight of such a composition. A preferred antioxidant is α-tocopherol (vitamin E).

Pharmaceutical formulations exhibit particularly beneficial oral properties; Thus, the indicators of consistency and a high level of bioavailability obtained in standard bioavailability tests are, for example, 2-4 times higher than those for emulsions. These tests are performed on animals, such as rats or dogs, or on healthy volunteers using HPLC or a set of specific or nonspecific monoclonal antibodies to determine the level of drug substance, for example macrolide, in the blood. So the composition indicated in Example 1, administered orally to dogs, can give unexpectedly high c _max values determined by ELISA (enzyme-linked immunosorbent assay) using a monoclonal antibody.

 Also high was the high predictability of pharmacokinetic parameters such as absorption and blood levels, which made it possible to eliminate or reduce the problems with the introduction associated with migratory absorption. In addition, the pharmaceutical compositions effectively interact with tensid substances, for example, bile salts present in the gastrointestinal tract. This means that the pharmaceutical compositions are completely dispersible in aqueous systems containing similar natural tensides, and are thus capable of forming in situ microemulsion systems that are stable and are not characterized by precipitation of the active agent or other destruction of the fine structure of the particles. The effect of the pharmaceutical compositions upon oral administration remains essentially independent and / or unaffected by the relative presence or absence of bile salts at any given time or in any given individual.

 The compositions of this invention reduce the inconsistency of the reaction to the administered dose for both one and between different patients.

 In a further aspect, the invention provides a process for the preparation of a pharmaceutical composition as defined above, comprising (1) hydrophilic phase; (2) lipophilic phase; and (3) a surfactant in a homogeneous mixture state and adding an active agent, for example cyclosporin or a compound of the macrolide class. If necessary, the composition can be formed in the form of a single dose, for example by packaging this composition in gelatin capsules.

 Possible additional components or additives, in particular an additional component of the hydrophilic phase, for example ethanol, can be mixed together with components (1), (2) and (3) or together or after adding the active agent.

 In order to obtain a microemulsion, the composition can be mixed with water or a water-based solvent.

 The authors of this application also consider the composition of microemulsion preconcentrates, which may not contain refined fish oil, and / or ethanol, and / or transesterified ethoxylated vegetable oil.

 The authors found that macrolides, in particular 40-O- (2-hydroxy) ethylrapamycin, are unstable during storage and can be subjected to a number of different degradation reactions. For example, after several days of storage, one or more degradation products can be identified using, for example, HPLC. Although further study of the pathways of degradation is still necessary, the authors suggest that rupture of the lactone ring in the macrolide may occur.

К настоящему времени установлено, что стабильные составы, содержащие макролиды, могут быть получены помещением макролида в кислую среду. При этом подразумевается, что составы стабильны, если вещество лекарства-макролида остается в основном интактно не поврежденным после нескольких дней или недель хранения при комнатной температуре (25^oС).The authors of this application have identified 40-O- (2-hydroxy) ethylrapamycin-2,34-secoacid as the main degradation product of 40-O- (2-hydroxy) ethylrapamycin. 40-O- (2-hydroxy) -ethylrapamycin-2,34-seco-acid, hereinafter referred to as seco-acid, has the following structure:

It has now been established that stable formulations containing macrolides can be obtained by placing the macrolide in an acidic environment. It is understood that the compositions are stable if the substance of the macrolide drug remains mostly intactly intact after several days or weeks of storage at room temperature (25 ^o C).

 In another aspect, the invention provides a pharmaceutical composition comprising macrolide and acid.

 The term macrolide is used in the same meaning as previously described.

В качестве примеров можно указать упомянутые выше и предпочтительно рапамицин или 40-О-(2-гидрокси)этилрапамицин.Preferred macrolides have at least one structure:

As examples, the aforementioned and preferably rapamycin or 40-O- (2-hydroxy) ethylrapamycin can be mentioned.

 Said acid may be soluble in lipids and / or ethanol. The acid may be, for example, a fatty acid, in particular oleic acid. Said acid may be a carboxylic acid, for example mono-, di- or tricarboxylic acid, and preferably mono- or dicarboxylic. The specified acid may contain one or more hydrophilic groups, for example hydroxyl groups, and preferably one or two hydrophilic groups. Suitable acids for use in this invention include malonic, fumaric, maleic, D-malic, L-malic, citric, ascorbic, succinic, oxalic, benzoic or lactic acids, or an acid with a similar pKa value, for example 2-7. Preferred acids are malonic, oxalic, citric and lactic acids. Malonic acid is most preferred.

 The preferred amount of acid can be determined using conventional experiments. The weight ratio of macrolide to acid in the composition according to this invention can have a value of up to 20: 1, for example from 1: 5 to 5: 1, in particular 1: 1. The specified acid may be present in an amount between 0.05 and 5% by weight of the composition.

 Macrolide may be present in an amount of from 1 to 15% by weight of the composition.

 The type of pharmaceutical composition is not critical. It may be a solid substance, but a liquid form is preferred. A macrolide, for example, can be incorporated into a microemulsion preconcentrate or emulsion preconcentrate as defined above and combined with a certain amount of acid. Such an acid-stabilized composition can be administered enterally, for example orally, namely in the form of a capsule or solution for drinking, or parenterally, namely in the form of an infusion concentrate. Oral administration is preferred.

 In a further aspect, the invention provides the use of an acid to stabilize a macrolide in a pharmaceutical composition.

 In another aspect, the invention provides a method for stabilizing a macrolide in a pharmaceutical composition, comprising admixing an acid with a macrolide.

 Thus, the invention contemplates obtaining stable formulations containing macrolides. Good bioavailability of the drug and reduction of variability in the response to the administered dose can be achieved both for one and between different patients.

 The effectiveness of all pharmaceutical formulations of the present invention can be observed in standard clinical tests, for example, according to known indications of doses of the active agent giving equivalent blood levels; for example, when doses are administered in the range from 2.5 mg to 1000 mg of active agent per day per 75 kilograms of the weight of a mammal, namely an adult, and in standard model animals. The increased bioavailability of the active agent provided by these formulations can be observed in standard animal tests or in clinical trials, such as those described above.

 The optimal dose of the active agent for administration to a particular patient should be carefully selected, since the susceptibility and metabolism of a macrolide compound, for example rapamycin, may vary between individuals. It may be appropriate to record the levels of the active agent in the blood plasma using radioimmunoassay, analysis using monoclonal antibodies or other suitable conventional methods. Doses of macrolide usually range from 1 to 1000 mg per day, for example from 2.5 mg to 1000 mg per day for an adult patient weighing 75 kilograms, preferably from 25 mg to 500 mg, with an optimal dose of from about 50 to 100 mg per day. Successful results were obtained with the administration of approximately 75 mg per day, for example, in the form of two capsules, one containing 50 mg and the other containing 25 mg; or three capsules, each 25 mg. Dosages of cyclosporin can be from 25 to 1000 mg per day (preferably from 50 mg to 500 mg), and a dose of FK506 from 2.5 mg to 1000 mg per day (preferably from 10 mg to 250 mg). For the introduction of 40-O- (2-hydroxy) ethylrapamycin, a dose between 0.5 and 5 mg / kg body weight / day is recommended.

 The pharmaceutical compositions are preferably combined in a single dose, for example, by filling them with capsule shells for oral administration. Capsule shells may be soft or hard gelatin capsule shells. If the pharmaceutical composition exists as a unit dose, then each unit dose will contain respectively from 10 to 100 mg of active agent, more preferably from 10 to 50 mg, for example 15, 20, 25 or 50 mg. Such unit doses are suitable for administration from 1 to 5 times daily, depending on the specific purpose of the treatment, phase of treatment, and the like.

 However, if necessary, the pharmaceutical compositions may be in the form of solutions for drinking and may include water or any other aqueous system to provide microemulsion systems suitable for drinking.

 These pharmaceutical formulations are particularly useful for the treatment and prophylaxis of the conditions described on pages 40 and 41 in EP 427680 and on pages 5 and 6 in PCT / EP 93/02604.

These pharmaceutical formulations are particularly useful for:
a) the treatment and prevention of rejection of organ or tissue transplants, for example, for the treatment of recipients of the following transplants: heart, lung, heart and lung, liver, kidney, pancreatic gland, skin or cornea. These pharmaceutical formulations are also indicated to prevent a graft versus host reaction, which sometimes occurs with bone marrow transplantation;
b) treatment and prevention of autoimmune disease and inflammatory conditions, in particular inflammatory conditions with an etiology, including an autoimmune component such as arthritis (for example, rheumatoid arthritis, chronic progressive arthritis and deforming arthritis) and rheumatic diseases;
c) treatment of multidrug resistance (MDR).

 In addition, these macrolide active agents exhibit antitumor and antifungal activity, and therefore, these pharmaceutical compositions can be used as antitumor and antifungal agents.

 The contents of all the references mentioned above, especially concerning compounds serving as an example (prototype), are given here as a reference, and each of the compounds given in the example can be used as macrolide in the examples illustrated below.

Examples
The following is a description by way of example, referring only to the compositions of this invention. The content of the components, unless otherwise indicated, is presented in weight percent for each composition.

Examples 1-20
The following is a description by way of example, referring only to the microemulsion preconcentrate formulations of this invention in which the hydrophilic phase comprises DMI or ethyl acetate.

 Examples 1 and 2 illustrate unit dosage formulations suitable for use, for example, for the prevention of transplant rejection or for the treatment of autoimmune diseases, and for administration in an amount of from 1 to 5 unit doses per day. Examples are described with specific reference to Ciclosporin, but equivalent formulations can be prepared using any macrolide or other active agent.

Example 1 (see table)
A batch of 1000 capsules is being prepared.

 Cyclosporin is dissolved with stirring at room temperature in (1), (2) and (3) are added to the resulting solution with stirring. Portions of the resulting mixture with a volume of 0.5 ml fill either capsules of size 1 made of hard gelatin, which are sealed using, for example, the QualiSeal technique, or soft gelatin capsules.

 Formulations containing 50 and 100 mg of Ciclosporin are prepared in a similar manner using the remaining specified ingredients in the indicated amounts.

 In this Example, refined oil is equivalent to “refined glycerol-transesterified corn oil” free of glycerol impurities [GB 2257359 and WO 94/09211].

Example 2
Preparation of oral solution for drinking
The composition is prepared analogously to Example 1, calculated on a volume of 5 liters, ethanol, if desired, can be replaced by an equivalent amount of dimethyl isosorbide.

Examples 3-19
Compositions with cyclosporin A are prepared using as a lipophilic phase:
Miglyol 812 (from Huls) - in Examples 3-9;
corn oil glyceride (mono-, di- and triglycerides from refined corn oil) in Examples 10-17;
Labrafil 2125 CS (from Gattefosse) - in Examples 18 and 19.

 In the following examples, DMI is used to denote dimethyl isosorbide.

 A filler is prepared by mixing the components with each other. Then cyclosporin A is dissolved in the carrier with stirring.

 Figure 1-5 presents triple diagrams of the relative concentrations of each of the hydrophilic, lipophilic and surface-active components. The relative concentration of DMI increases from 0 at the right edge of the diagram to 100% in the lower left corner, as indicated by the arrow. The relative concentration of the surfactant indicated in FIGS. 1-5 by the abbreviation S increases from the baseline of the diagram to 100% at the apex, as indicated by the arrow. The relative concentration of the lipophilic phase increases from 0 along the left edge of the diagram to 100% in the lower right corner, as indicated by the arrow. The lines inside the diagram indicate a 10% increase from 0 in each corner to 100% in the corresponding upper position.

 Thus, the theoretical composition, including 50% of the lipophilic phase and 50% DMI, is depicted in the diagram as a dot in the middle of the baseline.

 The relative proportions of the main components of the filler for the preferred formulations of the present invention lie within regions a and b, indicated by lines A and B in FIG. 1, respectively; areas c, d 'and d "marked with lines C, D' and D, respectively, in Figure 2; area e, marked by line E in figure 3; region f marked with a line F in FIG. 4, and region g marked with a line G in FIG. 5.

 In FIG. 1 and 2, Miglyol 812 is abbreviated as M. In FIGS. 3 and 4, corn oil glyceride is abbreviated as CG. 5, Labrafil 2125CS is abbreviated L.

Particle size measurement is carried out at 20 ^o With the dilution of 60 μl of the composition in 1 ml of water by correlation photon spectroscopy using, for example, Malvern ZetaSizer 3 from Malvern Instruments.

Examples 3-9 (See table 2 and 3)
Subsequent formulations containing cyclosporin A are prepared using Miglyol 812. Ethanol in the formulations of Examples 3 and 4 is present in an amount of 10% by weight.

 For compositions 3 and 4, no phase separation is observed, the compositions are transparent. When diluted with water in the ratio of 1: 1 and 1:10 by volume, the composition from Example 3 remains transparent. The composition from Example 4 opalescent when diluted with water in the ratio of 1: 1 and 1:10 (1 volume part of the composition, 10 volume parts of water). Figure 1 shows ternary diagrams for compounds 3 (region a) and 4 (region b).

 For none of the compositions 5–9 (see Table 3), no phase separation is observed; the compositions are transparent. When diluted with water in the ratio of 1: 1 and 1: 10 by volume, the compositions of Examples 5-9 remain transparent. Figure 2 shows ternary diagrams for each of the compositions 5-9 (areas c, d 'and d ").

Examples 10-17 (see table 4 and 5)
Compositions containing cyclosporin A in Examples 10-17 are prepared using corn oil glyceride. Ethanol in the compositions of Examples 10 and 11 is present in an amount of 10% by weight.

 For compositions 10 and 11, no phase separation is observed, the compositions are transparent. When diluted with water in the ratio of 1: 1 and 1:10 by volume, the compositions of Examples 10 and 11 remain transparent (1 part of the composition, 10 parts of water). Figure 3 shows ternary diagrams for compositions 10 and 11 (region e).

 For none of the compositions 12-17, no phase separation is observed, the compositions are transparent. When diluted with water in a ratio of 1:10 by volume (1 part of the composition, 10 parts of water) the compositions of Examples 12-17 remain transparent. When diluted with water in a ratio of 1: 1, the compositions of Examples 12, 13, 14, 15 and 17 remain transparent, and opalescence appears in the composition of Example 19.

 Figure 4 shows the triple diagrams of the compositions 12-17 (region f).

Examples 18 and 19 (see table 6)
Compositions containing cyclosporin A in Examples 18 and 19 are prepared using Labrafil 2125 CS as the lipophilic phase.

 For compositions 18 and 19, no phase separation is observed, the compositions are transparent. When diluted with water in the ratio of 1: 1 and 1:10 (1 part of the composition, 10 parts of water by volume), the composition of Example 19 remains transparent. When diluted with water in a ratio of 1: 1 and 1:10 of the composition from Example 18, opalescence appears. Figure 5 shows a triple diagram for composition 19 (region g).

 For compositions 3-19, the particle size distribution is measured. In all formulations, the maximum particle size is less than 70 nm. Z is the average particle size, lies in the range from 22.0 to 32.6 nm. The value of the polydispersity index lies in the range from 0.076 to 1.164.

Examples 20-24 (see table 7)
Microemulsion preconcentrates are prepared using ethyl acetate as the hydrophilic phase. To form an emulsion, the compositions are diluted with water in a ratio of 1: 1, as well as adding 10 parts of water to 1 part of the composition.

 According to visual observation, each of the compositions 21-24 after dilution forms a transparent and stable microemulsion.

Storage
The undiluted formulations of Examples 1-24 remain stable, i.e. no precipitation or crystallization was observed for at least one month of storage at room temperature. After two months of storage at room temperature, the compositions of Examples 5, 6, 7, 12 and 18 remain transparent.

Examples 25-27
Microemulsion preconcentrates are prepared and stored at room temperature for 12 months.

Example 25 - Amount in weight%
Cremophor RH 40 - 24
Corn Oil Glyceride - 48
DMI - 8
Ethanol abs. - 10
Cyclosporin A - 10
After 12 months of storage, no precipitation or crystallization is observed.

Example 26 - Amount in weight%
Cremophor RH 40 - 27
Corn Oil Glyceride - 54
DMI - 9
Cyclosporin A - 10
After 12 months of storage, no precipitation or crystallization is observed.

Example 27 - Amount in weight%
Cremophor RH 40 - 27
Corn Oil Glyceride - 45
DMI - 18
Cyclosporin A - 10
After 12 months of storage, no precipitation or crystallization is observed.

 Cyclosporin A can be replaced in any of the formulations described in Examples 1-27 with another cyclosporin or macrolide, for example rapamycin, 40-O- (2-hydroxy) ethylrapamycin, 33-epichloro-33-deoxyscomycin or the compound of Example 71 from EP 569337.

Examples 28-32
The following is a description in the examples of only acid-stabilized macrolide compositions.

Example 28
An active agent of class FK506 or class of rapamycin, for example 40-O- (2-hydroxy) ethylrapamycin, is introduced into the microemulsion preconcentrate of the following composition, expressed in weight percent: 2% active agent, 2% malonic, lactic or famonic acid, 44% Cremophor RH40 , 26.4% mono-, di-, triglycerides of corn oil, 17.6% 1,2-propylene glycol and 10% ethanol.

 Stability tests after 3 months showed that the composition with malonic acid contained by this time 98% of the active agent, and without malonic acid - only 73%.

Examples 29 and 30
Microemulsion preconcentrates are prepared using 40-O- (2-hydroxy) ethyl rapamycin in Examples 29a and 296 and rapamycin in Examples 30a and 30b as the active agent. In Example 29, the active agent 40-O- (2-hydroxy) ethyl rapamycin is abbreviated as “active agent R”.

 The content of the intact drug and the degradation product were determined by HPLC with a measurement error of ± 2% (see table 8).

 The content of the main degradation product is indicated in parentheses. The main degradation product of rapamycin is called secorapamycin.

 The above examples demonstrate that malonic acid has a pronounced stabilizing effect on 40-O- (2-hydroxy) ethyl rapamycin and rapamycin.

Example 31
The composition of Example 29a is mixed with malonic acid in concentrations ranging between 0.05 and 5% by weight. A highly stabilizing effect is observed with malonic acid in the concentration range from 0.25 to 0.75% by weight of the composition.

Example 32
The concentrate for infusion is prepared using the following composition:
40-O- (2-Hydroxy) ethylrapamycin - 20 mg / ml
Cremophor EL - 600 mg / ml
Citric Acid - 10 mg / ml
Ethanol - Up to 1 ml
After storage at 25 ^{° C.} for 4 weeks, measuring the active ingredient content gives a value of 99.6%. This result demonstrates the stabilizing effect of citric acid on 40-O- (2-hydroxy) ethylrapamycin.

 In the Examples 28-32 above, the active agent can be replaced with 33-epichloro-33-deoxy-succinicin or with compound 71 of EP 569337.

Claims (5)

 1. A microemulsion preconcentrate comprising a sparingly soluble active agent and a carrier containing 1) a hydrophilic phase containing dimethyl isosorbide and / or lower alkyl alkane ether, 2) a lipophilic phase, 3) a surfactant.  2. A preconcentrate according to claim 1, characterized in that the active agent is cyclosporin or macrolide.  3. A preconcentrate according to claim 1 or 2, characterized in that the active agent is selected from cyclosporin A, rapamycin, 40-O- (2-hydroxy) ethylrapamycin, 33-epichloro-33-deoxy-succinicin, FK506 or ascomycin.  4. The preconcentrate according to any one of paragraphs. 1-3, characterized in that the hydrophilic phase contains ethyl acetate as a lower alkyl alkane ether.  5. The preconcentrate in paragraphs. 1-4 for oral or parenteral administration. Priority on points:
November 2, 1994 according to 1-5, except for p. 1 - lower alkyl alkane ether - 10.25.1995; p. 3 - 33-epichloro-33-deoxyascomycin - 08/22/1995; p. 4 - ethyl acetate - 12/15/1994; p. 5 - parenteral administration - 10/25/1995.

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