CA2124443A1 - Methods and compositions for treating infection using optically pure (s)-lomefloxacin - Google Patents

Abstract

Methods and compositions are disclosed utilizing the optically pure (S)-isomer of lomefloxacin. This compound is a potent drug for the treatment of infection or other diseases requiring antibiotics while avoiding the concomitant liability of adverse effects that are associated with the racemic mixture of lomefloxacin.

Description

WO93/1078~ ~l 2 ll 4 ~ ~ PCT/US92/10142 METHODS AND COMPOSITIONS FOR TREATING INFECTION
USING OPTICALLY PURE (S~-LOMEFLOXACIN

1. BACKGROUND OF THE INVENTION :~
This invention relates to novel compositions ~.
of matter containing optically pure (S)-lomefloxacin.
These compositions possess potent activity in treating -various infections while avoiding adverse effects 10 associated with racemic lomefloxacin including but not -~
limited to headache, stomach discomfort, ~
gastrointestinal disorders, hypoglycemia, renal and ~ :
hepatic dysfunction, allergic reactions and ~:
~-~ respiratory distress, and arthropathy, such as cartilage lesions and erosion and abnormalities in -bone growth in immature patients. Additionally, these -~;
novel compositions of matter containing optically pure (S)-lomefloxacin are useful in treating infection in ;::~
those ~atients with impaired renal function. Al~o ~
20 disclosed are methods for treating the above-described :
conditions in a human while avoiding adverse effects that are associated with the racemic mixture of :
lomefloxacin, by administering the (S)-isomer of lomefloxacin to said human.
:
1.1 Steric Relationship and Drug Actio~ ~;~
Many organic compounds exist in optically ~:
active forms, i.e., they have the ability to rotate the plane of plane-polarized }ight. In describing an optically active compound, the prefixes D and L or R
and S are used to denote the absolute configuration of the molecule about its chiral center(s). The prefixes d and 1 or (+) and (-) are employed to designate the sign of rotation of plane-polarized light by the compound, with (-) or 1 meaning that the compound is levorotatory. A compound prefixed with (+) or d is ': .' . .

dextrorotatory. For a given chemical structure, these compounds, called stereoisomers, are identical except that they are mirror images of one another. A
specific stereoisomer may also be referred to as an enantiomer, and a mixture of such isomers is often called an enantiomeric mixture. A SO:50 mixture of enantiomers if referred to as a racemic mixture.
Stereoch~mical purity is of importance in the field of pharmaceutical-~, where 12 of the 20 most prescribed drugs exhibit chirality. A case in point is provided by the L-form of the ~-adrenergic blocking agent, propranolol, which is known to be lO0 times more potent than the D-enantiomer.
Furthermore, optical purity is important since certain isomers may actually be deleterious rather than simply inert. For example, it has been suggested that the D-enantiomer of thalidomide was a safe and effective sedative when prescribed for the control of morning sickness during pregna~cy, and that the corresponding L-enantiomer was a potent teratogen.

l.2 Racemic Lomefloxacin Lomefloxacin is described in United States Patent No. 4,528,287 and Japan Patent Publication No.
64~79 (1985). Lomefloxacin is currently available commercially in Argentina, Japan, Mexico, and other countries in Asia and Eastern Europe, as the racemic mixture, i.e., it is a l:l mixture of optical isomers. ~.
It is the optically pure, or substantially optically 30 .pure (S)-isomer of lomefloxacin, which is the subject .
of the present invention, hereinafter referred to as (S)-lomefloxacin.
Racemic lomefloxacin, having the chemical name l-ethyl-6,8-difl.uoro-l,4-dihydro-7-(3-methyl-l-35 piperazinyl) 4-oxo-3-quinolinecarboxylic acid, belongs ~:

WO93t10785 ~ ~ 2 ~ 3 PCT/US92/10142 ~;

to the quinoline class of antibiotics. The quinoline ~ -~
antibiotics, in general, exhibît a broad spectrum of antibacterial action, demonstrating effectiveness ~;
against both Gram-positive and Gram-negative bacterial 5 strains. Quinoline antibiotics have been shown to be ;~
effective in treating infections of the respiratory, genito-urinary, and gastrointestinal tracts. They have also demonstrated utility in the treatment of patients with cystic fibrosis and pulmonary infections. Effectiveness has also been demonstrated in the treatment of intra-abdominal, bone and joint, skin, soft-ti&sue, pelvic, and eye, ear, nose, and ;
throat infections.
The quinoline antibiotics derive their ~-~
activity through inhibition of the bacterial enzyme, DNA gyrase, which is responsible for catalyzing the bacterial DNA supercoiling necessary to pack DNA
filaments into bacterial cells. This inhibition causes irreversible chromosome damage leading to ~ ;
bacterial cell death. The selectivity of quinoline antibiotics for bacterial cells is the result of the supercoiling mechanism in eukariotic cells being mediated by a different set of enzymes not susceptible "
to quinoline inhibition. Quinoline antibiotics are 25 also thought to interfere with proper bacterial cell ~`
membrane function, also contrîbuting to cell death.
The first quinoline antibiotic to be commercialized, nalidixic acid, was discovered following the observation that the structurally `
simiIar 6-chloro-lH-ethyl-4-oxoquinolone-3-carboxylic acid, a minor by-product of the commercial production of the antimalarial agent chloroquine, exhibited weak antibacterial action. Since the discovery of nalidixic acid, some 7,000 analogs belonging to approximats}y 16 different ring systems have been ', ,~,.. .

~ 3 WO93/107~5 P~T/US92/10142 synthesized and tested for antibacterial action. From this data, a comprehensive structure/activity relationship has been elucidated.
Structural activity studies have demonstrated that substitution at position l and a carbonyl ~ubstitution at position 4 on the quinoline ~`~
ring appear to be required for antimicrobial activity. ~;~
No substitution at position 2 and a carboxyl function at position 3 also appear to be required for activity.
The only exception appears to be a thiazolidone ring fused at positions 2 and 3. Depending on modification, the presence of additional fused rings, ~- as well as various ring substitutions, can be either beneficial or detrimental to activity.
-~
Fiqure l R o 6 ~ CO~I

:
Racemic lomefloxacin exhibits a broad spectrum of antibacterial action, demonstrating effectiveness against both gram-positive and gram-negative bacterial strains. Lomefloxacin has shown to be more effective against Gram-negativ~ bacteria. In particular, lomefloxacin has shown excellent bacteriocidal activity against strains of Enterobacteriaceae, Haemophilus influenzae, Neisseria gonorrhoeae, Branhamella catarrhalis , L.
pneumophilia, and good-to-moderate activity against strains of Acinetobacter,.Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis, .. .

WO93/10785 2 12 ~ 4 ~ 3 PCT/US92/10142 but poor ac~ivi~y against Pseudomonas cepacia. There is only a low propensity for bacteria to develop a -~
resistance to lomefloxacin by spontaneous mutation.
However, development of resistance is facilitated when ;~
bacteria are exposed to sub-inhibitory concentrations of the antibiotio.
Lomefloxacin has an average elimination half-life of approximately 8 hours with peak plasma concentrations occurring at approximately l hour after ~-10 oral dosing in humans. Its long half-life and dose ~ ;
proportionality have lead to introduction of ~-lomefloxacin ~s the first, once-daily 4-quinoline antibiotic.
.. ~ .
Furthermore, unlike ciprofloxacin, lomefloxacin does not interfere with the metabolism of theophylline. Likewise, co-administration of ranitidine with lomefloxacin has no effect on lomefloxacin's pharmacokinetics. However, co-administration of sucralfate with lomefloxacin, -~
presumably through aluminum complexation, does reduce the absorption of the antibiotic. In patients with reduced renal function, lomefloxacin exhibits reduced renal clearance, with a con~equential prolongation of the half-life by up to 24 hours. Antibacterial levels 25 of lomefloxacin are therefore maintained in patients ` i with reduced renal function for up to five days.
Little is known about the phaxmacology of the individual isomers of lomefloxacin. The pure ;
enantiomer form of ofloxacin, a related quinoline antibiotic, has been studied (Antimicrob. Agents . ~, Chemother., 1988, 32(9), 1336-1340~. The (S)-isomer of ofloxacin has been reported to be twice as potent a bactericide as the racemate against a variety of gram~
positive and gram-negative pathogens.

wos~ PCT/US92/10142 The racemic mixture of lomefloxacin is presently used primarily as an antibiotic agent for treatment of infection of the upper respiratory and urinary tract. Viral infections of the respiratory tract are acute illnesses with local and systemic manifestations. Coryza (common cold), pharyngitis, laryngitis (including croup), and tracheobronchitis are common respiratory syndromes. See, for example, Merck Manual 5th Ed., p. 169, Merck, Sharpe & Dohme Research Laboratories ~1987). Bacterial infections of the lower urinary tract are very common. The majority `~
of urinary trapt infections are caused by gram-negative bacteria. Organisms gaining access to ~he urethra may colonize on the periurethral glands and produce acute and chronic inf ection. This condition is termed urethritis. Infections of the prostate gland give rise to the condition prostatitis.
Enteric, gram-negative organisms are the most common cause of prostate infection. Merck Manual 5th Ed., p.
1610, Merck, Sharpe & Dohme ~esearch Laboratories (1987).
Additionally, racemic lomefloxacin has also been used in treating enteritis, sexually transmitted diseases, obstetric and gynecologicaI infections, surgical infections, skin, soft tissue and joint infections, otorhinolaryngologic infections and ophthalmological infections.
Although lomefloxacin and quinoline antibiotics have several advantages, they also ha~e disadvantages, namely, adverse effects. The adverse effects of quinoline antibiotics in general include arthropathy, headache, stomach discomfor~, gastrointestinal disorders, hypoglycemia, renal and hepatic dysfunction, allergic reactions and reæpiratory distress, and ~entral nervous system W093/10785 ~12 14~3 PCT/VS92/10142 :;

effects including convulsions, increased intracranial ~;
pressure, and toxic psychoses. ~he adverse effects of ~;
lomefloxacin, in particular, include but are not ~:
limited to headache, stomach discomfort, gastrointestinal disorders, and arthropathy, such as cartilage lesions and erosion and abnormalities in bone growth in immature patients. Thus, it would be particularly desirable to find a compound with the advantages of the racemic mixture of lomefloxacin which would not have the aforementioned disadvantages.

2. SUMMARY OF THE INVENTION
It has now been discovered that the optically pure (S)-isomer of lomefloxacin is effective ;
in treating infection in a human. Further, it has also been discovered that the optically pure .:.
(S)-isomer of lomefloxacin is effective in treating infection in a human while avoiding adverse effects .
associated with the administration of racemic 20 lomefloxacin, including but not limited to headache, ~.
stomach discomfort, gastrointestinal disorders, hypoglycemia, renal and hepatic dysfunction, allergic ~:
reactions and respiratory distress, and arthropathy, .
such as cartilage lesions and erosion and abnormalities in bone growth in immature patients.
The present invention also includes methods for treating the above-described conditions in a human ~:
while avoiding the adverse effects that are associated with the racemic mixture of lomefloxacin, by administering the optically pure (S)-isomer of lomefloxacin to said human. ;~

3. DETAILED DESCRIP~rION OF THE INVENTION :~
The present invention is a method of treating infection in a human which comprises 2 ~ ~ f~

administering to the human, an amout of (S)-lomefloxacin, or a pharmaceutically acceptable thereof, substantially free of its (R~-stereoisomer, said amount being sufficient to alleviate infection.
The present invention encompasses a method of treating infection in a human while avoiding the concomitant liability of adverse effects associated with the administration of racemic lomefloxacin, which comprises administering to said human, an amount of (S~-lomefloxacin, or a pharmaceutically acceptable salt thereof, substantially free of its (R)-stereoisomer, said amount being sufficient to :;
alleviats infection, but insufficient to cause ~aid ~:~
adverse effects associated with administration of ;;~
racemic lomefloxacin.
The present invention also encompasses an antibiotic composition for treating infection in a human which comprises, an amount of (S)-lomefloxacin or a pharmaceutically acceptable salt thereof, substantially free of its (R)-stereoisomer, said amount being sufficient to alleviate said infection but insufficient to cause adverse effects associated with lomefloxacin.
The available racemic mixture of lomefloxacin (i.e., a 1:1 mixture of the two enantiomers) possesses antibiotic activity, and provides therapy and a reduction of symptoms in a variety of conditions and disorders related to bacterial infection; however, this racemic mixture, -:;~
while offering the expectation of efficacy, causes adverse effects. Utilizing the substantially optically pure (S~-isomer of lomefloxacin results in :~`
clearer dose-related definitions of efficacy, diminished adverse effects, and accordingly, an ~`~

.,'~ `.

WO93/10785 2 1 2 ll '1 4 3 PCT/uSs~/10142 g _ . .

improved therapeutic index. It is therefore, more desirable to use the (S)-isomer of lomefloxacin.
The term 'ladverse effects" includes, but is not limited to headache, stomach discomfort, 5 gastrointestinal disorders, hypoglycemia, renal and -~-hepatic dysfunction, allergic reactions and respiratory distress, and arthropathy, such as cartilage lesions and erosion and abnormalities in bone growth in immature patients. ~ ~~
The term "substantially free of its (R)-stereoisomer'~ as used herein means that the composition contains a greater proportion of the (S)~
isomer of lomefloxacin in relation to the (R)-isomer ~.--of lomefloxacin. In a preferred embodiment the term 15 "substantially free of its (R)-isomer" as used herein ~;
means that the composition contains at least 90% by weight of (S)-lomefloxacin, and 10% by weight or less of (R)-lomefloxacin. These percentages are based on the total amount of lomefloxacin present in the composition. In the most preferred embodiment the term "substantially free of the (R)-stereoisomer"
means that the composition contains at least 99% by weight (S)-lomefloxacin, and 1% or less of (R)-lomefloxacin. In another preferred embodiment, the term "substantially free of its (R)-stereoisomer" as used herein means that the composition contains 100%
by weight of (S)-lomefloxacin. The terms "æubstantially optically pure (S~-isomer of lomefloxacin" and "optically pure (S)-isomer of lomefloxacin" are also encompassed by the above-described amounts.
The term "amount sufficient to alleviate -~
infection" as used herein means an amount which eliminates or inhibits the growth of foreign ~5 `;;

: ' WO93/10785 PCT/US92/10~42 ~

-- 10 - . .

microorganisms that are harmful to the normal functioning of the host organism, particularly humans. : ;
The chemical synthesis of the racemic ::
mixture of lomefloxacin can be performed by the method :~
described i~ United States Patent No. 4,528,287. The method involves the reaction of 1,4-dihydro-4-oxoquinoline-3-carboxylic acid 2 (where X=Cl or F) with piperazine 1. The preparation of the type 2 compou~ds has previously been described in Japanese Patent Publication No. 141286/1978, Japanese Patent Publication No. 47658/1980 and Japanese Patent Publication No. 30964/1981.
~- Fiqure 2 I~Nr$ ~ 1~2 C 13 ~ 5 IX~f2~

F C21~S ~
C113 ' Furthermore, the (S)-isomer of lomefloxacin :~
may be obtained by resolution of the mixture of enantiomers of lomefloxacin~using conventional means such as an optically actlve resolving acid; see, for ~:~
3 examplè "Stereochemistry of Carbon Compounds," by D.L.
Eliel ~McGraw Hill 1962) and Lochmuller, C.H. et al., :.
J. Chromatoqr. 113:(3) 283-302 (1975). (S)~
Lomefloxacin can be prepared from the racemate through ~:-the diastereomeric crystallization scheme shown below: -~`
';.'1 WO 93/1078~ 212 ~ l 1 3 PC~/US92/10142 Fiqure 3 ;-. ~ ;, l~C02~

11~ F C2155 ¦ Op~ic~lly purc aminc ~OP~
~ ~'''`~.
O O ``
10P~o2 ~llorA F~ fO2 IIPA ~ .;

HN ~ ~ c2115 ~IN~J ~ C21~5 i-~
~_ CII C113 ` 15 o o ~ ~ ~ ~ o~

.~IN~ F C21iS I~N J ~ C211S ~ ~ .
C~3 CI~3 R S

Racemic lomefloxacin is treated with an ::
optically pure base (an amine is shown above) to give a pair of diastereomeric salts. The difference in 25 solubility between the two~diastereomers allows one to `:
be selectively crystallize~ from the solvent while the other remains in solution. Crystals of the single diastereomer~are then separated from the other ;`
diastereomer by filtration. Once separated, the 3~ diaste~eomers can be converted back to the original enantiomers by treatment with acid.
The magnitude of a prophylactic or therapeutic dose of (S)-lomefloxacin in the acute or `
chronic management of disease will vary with the ;~
severîty of the condition to be treated and the route ;

W093/107~ 2 ~ PCT/US92/10142 ~ 12 -of administration. The dose, and perhaps the dose frequency, will also vary according to the age, body weiqht, ~nd re~ponse of the individual patient. In general, the total daily dose ranges, for the conditions described herein, is from about lO0 mg to about 400 mg. However, the dosage may be as high as about 800 mg. Preferably, a daily dose range should be between about lO0 mg to about 200 mg. In managing the patient, the therapy should be initiated at a lower dose, perhaps about lO0 mg to about 200 mg and increased up to about 400 mg or higher depending on the patient's ~lobal response. It is further recommended that children, patients over age 65, and those with impaired renal or hepatic function, initially receive low doses. Those dosages should also be titrated based on global response and blood level. In some cases, it may be necessary to use dosages outside these ranges in some cases.
The term, "an amount sufficient to alleviate înfection but insufficient to cause said adverse effects," is e,compassed by the above described dosage amounts and dose frequency schedule.
The term, "method of treating infection" as used herein, includes but is not limited to infections such as urinary tract infection, upper respiratory tract infection, sexually transmitted infection, ophthalmological infection, gastrointestinal infections such as those caused by H. pylori and any ~
other infections which may arise in cells or tissues ;`
30 of a human and which require treatment with -~-antibiotics. i,:,.
Any suitable route of administration may be employed for providing the patient with an effective ~;
dosage of (S)-lomefloxacin. For example, oral, rectal, parenteral, transdermal, subcutaneous, WO93/1078~ 21~ ~ 14 3 PCTtUS92/10142 intramuscular, and the like may be employed as appropriate. Dosage forms include tablets, coated tablets, troches, dispersions, suspensions, solutions, caplets, capsules, patches, and the like.
The pharmaceutical compositions of the present invention comprise (S)-lomefloxacin as active in~redient, or a pharmaceutically acceptable salt thereof, and may also contain a pharmaceutically acceptable carrier, and optionally, other therapeutic ingredients. (S)-lomefloxacin hydrochloride is a pharmaceutically acceptable salt of (S)-lomefloxacin.
The most preferred pharmaceutically acceptable salt of (S) lomefloxacin is the monohydrochloride salt. ~
The term "pharmaceutically acceptable salts" ~;
~5 refers to salts prepared from pharmaceutically acceptable non-toxic acids or ~ases including inorganic a~ids and bases and organic acids and bases. ~`
Since the compound of the present invention ~
is both basic and acidic, salts may be prepared from `;~-pharmaceutically acceptable non-toxic acids or bases including inorganic and organic acids or inorganic and organic bases. Such salts may contain any of the following anions: acetate, benzensulfonate, benzoate, camphorsulfonate, citrate, fumarate, gluconate, hydrobromide, hydrochloride, lactate, maleate, mandelate, mucate, nitrate, pamoate, phosphate, succinate, sulfate, tartrate and the like.
Particularly preferred are benzensulfonate, hydrobromate, hydrochloride and sulfate. Such salts may also contain the following cations: aluminum, calcium, lithium, magnesium, potassium, sodium, zinc, benzathine, chloroprocains, choline, diethanolamine, ethylenediamine, meglumine, and procaine. ~`
The compositions include compositions suitable for oral, rectal and parenteral (including WO93/10785 21 2 ~ PCT/US92/10142 subcutaneous, intramuscular, and intraven~us) administration, although the most suitable route in any given case will depend on the nature and severity of the condition being treated. The most preferred route of the present invention is the oral route. The compositions may be con~eniently presented in unit ~-dosage form, and prepared by any of the methods well known in the art of pharmacy. -In the case where an oral composition is employed, a suitable dosage range for use is e.g., from about lO0 mg to about 400 mg total daily dose, given as a onc~ daily administration in the morning or in divided doses if required. Preferably, a dose of -,> --400 mg is given as a once daily administration. More preferably, a dQse range of between about lO0 mg to about 200 mg is given as a once daily administration or in divided doses if required. Patients may be upward titrated from below to within this dose range to a satisfactory control of symptoms. ;
In practical use, (S)-lomefloxacin can be combined as the active ingredient in intimate admixture with a pharmaceutical carrier according to ;~
conventional pharmaceutical compounding techniques. ;;~
The carrier may take a wide variety of forms depending ;~
on the form of the preparation desired for administration, e.g., oral or parenteral (including intravenous injections or infusions). In preparing the compositions for oral dosage form any of the usual pharmaceutical media may be employed. Usual 30 pharmaceutical media includes, for example, water, -~
glycols, oils, alcohols, flavoring agents, `~
preservatives, coloring agents, and the like in the case of oral liquid preparations (such as for example, ;~
suspensions, solutions, and elixirs); aerosols; or 35 carriers such as starches, sugars, microcrystalline ~-'' WO93/10785 2 1 ~ 3 PCT/US92/iO142 - 15 - ~.

cellulose, diluents, granulating agents, lubricants, binders, disintegrating agents and the like, in the `
case of oral solid preparation~ (such as for example, powders, capsules, and tablets) with the oral olid preparations being preferred over the oral liquid preparations. The most preferred oral solid ~
preparation is tablets. :~-Because of their ease of administration, tablets and capsules represent the most advantageous 0 oral dosage unit form, in which case solid pharmaceutical carriers are employed. If desired, tablets may be coated by standard aqueous or . nonaqueous techniques. The parenteral dosage form can consist of a sterile solution of the active :~
ingredient, either in its free or salt form, in physiological buffer or sterile water.
In addition to the common dosage forms set :~
out above, the compounds of the present invention may also be administered by controlled release means and/or delivery devices such as those described in U.S. Patent Nos.: 3,845,770; 3,gl6,89~; 3,536,809;
3,598,123; 3,630,200; 4,008,719; 4,~87,660 and 4,769,207, the disclosures of which are hereby incorporated by reference. s . 25 Pharmaceutical compositions of the present invention suitable for oral administration may be presented as discrete units such as capsules, cachets, or tablets, or aerosols sprays, each containing a ;~
predatermined amount of the active ingredient, as a 30 powder or granules, or as a solution or a suspension ~;
in an aqueous liquid, a non-aqueous liquid, an oil-in~
water emulsion, or a water-in oil liquid emulsion.
Such compositions may be prepared by any of the methods of pharmacy, but all methods include the step ~`
of bringing into association the active ingredient 5 2 1 2 1 1 4 3 P~T/US92/10142 !

with the carrier which constitutes one or more necessary ingredients. In general, the compositions are prepared by uniformly and intimately admixing the active ingredient with liquid carriers or finely divided solid carriers or both, and then, if necessary, shaping the product into the desired presentation.
For example, a tablet may be prepared by compression or molding, optionally, with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active ingredi~ent in a free-flowing form such as . powder or granules, optionally mixed with a binder, lubricant, inert diluent, surface active or dispersing $5 agent. Molded tablets may be made by molding in a `
suitable machine, a mixture of the powdered compound moistened with an inert liquid diluent. Desirably, each tablet contains from about lO0 mg to about 200 mg of the active ingredient, and each cachet or capsule 20 contains from about lO0 mg to about 200 mg of the -active ingredient, (S)-lomefloxacin. Most preferably, the tablet, cachet or capsule contains either one of two dosages, about lO0 mg or about 200 mg of the active ingredient.
The invention is further defined by reference to the following examples describing in detail, the preparation of the compound, an~ the compositions of the present invention. It will be apparent to those skilled in the art, that many ~;
modificationsr both to materials, and methods, may be practiced without departing from the purpose and interest of this invention. -'i'~

WO 93tlO785 ~ ;L 2 ~l 9~ l~ 3 PCI`/US92/10142 - 17 ~
!
: ,:
4. EXAMPLES :~
4.1 EXAMPLE 1 ORAL FORMULATION :~
Capsules: :.
S .. ` ~.
: .:
Formula Quantity per Capsule ~;.
in mg.

Active Ingredient (S)-lomefloxacin hydrochloride 100 200 ~
Lactose 349 249 -Corn Starch ~0 50 :~:
Magnesium St~arate 1.0 1.0 Compression Weight So0 500 .

The active ingredient, ~S)-lomefloxacin, lS lactose, and corn starch are blended until uniform. ;~
The magnesium stearate is then blended into the resulting powder. The resulting mixture is encapsulated into suitably sized two-piece hard .~:
gelatin capsules.

~ ;~
~, .

: ~
~'.'`''``~

WO93/10785 ~ PCT/US~2/10142 ;~
,: '~ ,'.,, - 18 ~

4.2 EXAMPLE 2 -~;
ORAL ORMULATION
Tablets :;;

Formula Quantity per Tablet in mg.
, ~.,-Active Ingredient (S)-lomefloxacin hydrochloride l00 200 ~0 Lactose BP 309 209 ~-.
Starch BP 60 60 Pregelatinized Mai~e Starch BP30 30 .
Magnesium Stearate l l ,:.
Compression Weight 500 500 The active ingredient is sieved through a suitable sieve and blended with lactose, starch, and .
pregelatinized maize starch. Suitable volumes of purified water are added and the powders are `~-granulated. After drying, the granules are screened ... .
and blended with the magnesium stearate. The granules are then compressed into tablets using punches. :~
Tablets of other strengths may be prepared by altering the ratio of active ingredient to lactose ~;
or the compression weight and using punches to suit. -.
~.

~ .:

~ `~
, ~ ~ "

-~

. ~

WO 93/10785 212 ~ l1 4 c~ PCI`/US92/10142 -- lg --4 . 3 EXAMPLE 3 .
INTRAVENOUS _FORMULATION

Formula Quantity per 10U mL

Active Ingredient (S)-lomefloxacin lactate 20 mg Sterile Water 100 mL

Intravenous infusion solutions of (S)-lomef loxacin may also be prepared with Sodium Chloride Injection USP 0.9% or Dextrose Injection USP 5%.

4.4 EXAMPLE 4 The anti-bacterial activity of (S)- .
lomefloxacin towards specif ic microorganisms is assessed by determination of the minimal inhibitory concentration (MIC) of the compound that prevents growth of that microorganism under assay conditions.
Cultures of various gram-negative and gram-positive bacteria, including obligate anaerobes, are grown in various standard media suited to the particular microorganism of interest. ~ee, for example, Sato, K. et al., Antimicrob. Agents and ::
Chemotherapy, 22(4): 548-553 (1982).] Isolates are grown overnight at 37C and adjusted to the density of a 0.5 McFarland standard (i.e., about 108 cFu/mL), and then diluted to 10 2. One loopful of cells ~5 ~L) of each diluted cultùre (approximately 1000 cells) is then inoculated onto 10-mL drug-containing agar layers in Petri dishes using a multi-point inoculator.
Following inoc~lation, agar plates are incubated for 18 hours at 37C in air with the exception of the obligate anaerobes, which are incubated in an atmosphere containing 10% CO2. The MIC is defined as WO93/10785 ~ 3 PCT/US92/10142 the lowest concentration of (S)-lome~loxacin that completely prevents the visible grow~h of the inoculum .~
on the surface of the (S)-lomefloxacin-containing ;
medium.
Testing for quinolone-in~uced arthropathy can be accomplished by administering the quinolone at a suitable dose, on a once-daily basis, to 3-4 month ~:
old, skeletally immature Beagle dogs, for l, 2, 5, or 7 days. A placebo is given to a second group of ~-Beagle dogs to act as a control. A scoring technique that includes lesion size and histologic features is :~
used to determine the progression of the lesions.

4.5 EXAMPLE 5 ..
TEST OF HEPATOTOXICITY

Microsomal Preparation Hepatic microsomes are prepared from human liver. Tissue is thawed and then homogenized in 0.15 : `:
20 M KCl in a Polytron homogenizer. The homogenate is ^~:
centrifuged and the pellet is r~suspended and homogenized in 0.15 M KCl. Aliquots are frozen and stored at -70C. :~

Lymphocyte PreDaration Human lymphocytes are aseptically isolated from fresh, heparinized human blood. Blood is diluted with Eagle's minimal essential medium and layered on ~:
Ficoll-Paque. The samples are centrifuged, and ~;;
~0 lymphocytes are then removed from the aqueous-Ficoll interface and suspended in medium (15 Mm 4-(2 hydroxyethyl)-l-piperazine ethane sulfonic acid ~HEPES~, pH 7.4). The cells are then centrifuged, ~.
washed once in the HEPES medium, and resuspended.
~`~

WO 93/10785 2 12 !1 4 4 3 PCT/US92/10142 _ncubation Conditions and Cvtotoxic Assav Cytotoxicity is assessed by the conversion of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diph~nyl tetrazolium bromide) to a purple formazan~ The conversion of MTT to dye is done in multiwell plates.
After preparation, hepatic microsomes or lympho~ytes are incubated alone or wi~h the test compound in a concentration range from 1 to 400 ~M at 37C in a humidified incubator. After incubation, the microsomeslcells are washed with 5% albumin in HEPES-buffered medium and resuspended. The microsomes/cells are then incubated at 37C in a humidified incubator.
. Af~er the incubation, 125 ~g of MTT is added to each well. The plates are incubated at 37C and ;~
15 centrifuged. After centrifugation, 100 ~L of ;
isopropanol is added and, after incubation, the optical density is determined using an automated plate-reader.

:, :

Claims (24)

What is claimed is:

1. A method of treating infection in a human, which comprises administering to a human, an amount of (S)-lomefloxacin, or a pharmaceutically acceptable salt thereof, substantially free of its (R)-stereoisomer, said amount being sufficient to alleviate infection.

2. A method of treating infection in a human while avoiding the concomitant liability of adverse effects associated with the administration of racemic lomefloxacin, which comprises administering to a human, an amount of (S)-lomefloxacin, or a pharmaceutically acceptable salt thereof, substantially free of its (R)-stereoisomer, said amount being sufficient to alleviate infection, but insufficient to cause said adverse effects associated with administration of racemic lomefloxacin.

3. The method of claim 2 wherein said adverse effects are selected from the group consisting of headache, stomach discomfort, gastrointestinal disorders, arthropathy and abnormalities in bone growth in immature patients.

4. The method of claim 2 wherein said adverse effects are selected from the group consisting of hypoglycemia, renal dysfunction, hepatic dysfunction, allergic reactions and respiratory distress.

5. The method of claim 1 or 2 wherein (S)-lomefloxacin is administered by intravenous infusion, transdermal delivery, orally as a tablet or a capsule.

6. The method of claim 1 or 2 wherein the amount administered is from about 100 mg to about 800 mg.

7. The method of claim 6 wherein the amount administered is from about 100 mg to about 400 mg.

8. The method of claim 7 wherein the amount administered is from about 100 mg to about 200 mg.

9. The method of claim 1 or 2 wherein the amount of (S)-lomefloxacin or a pharmaceutically acceptable salt thereof is greater than approximately 90% by weight.

10. The method of claim 1 or 2 wherein the amount of (S)-lomefloxacin or a pharmaceutically acceptable salt thereof, substantially free of its (R)- stereoisomer is administered together with a pharmaceutically acceptable carrier.

11. The method according to claims 5, 6, 7, or 8, wherein (S)-lomefloxacin is administered as a hydrochloride salt.

12. The method of claim 1 or 2 wherein said infection is selected from the group consisting of urinary tract infections, upper respiratory tract infections, sexually-transmitted infections, ophthalmological infections, and intestinal infections.

13. An antibiotic composition for treating infection in a human, which comprises an amount of (S)-lomefloxacin or a pharmaceutically acceptable salt thereof, substantially free of its (R)- stereoisomer, said amount being sufficient to alleviate infection, but insufficient to cause adverse effects associated with lomefloxacin.

14. A composition according to claim 13 wherein said adverse effects are selected from the group consisting of headache, stomach discomfort, gastrointestinal disorders, arthropathy and abnormalities in bone growth in immature patients.

15. A composition according to claim 13 wherein said adverse effects are selected from the group consisting of hypoglycemia, renal dysfunction, hepatic dysfunction, allergic reactions and respiratory distress.

16. A composition according to claim 13 wherein the amount is about 100 mg to about 400 mg.

17. A composition according to claim 13 wherein said composition is administered from one to four times a day.

18. A composition according to claim 17 wherein said composition is administered once a day.

19. A composition according to claim 13 which comprises the hydrochloride salt of (S)-lomefloxacin.

20. A composition according to claim 19 wherein said composition is adapted for oral administration.

21. A composition according to claim 19 adapted for intravenous delivery.

22. A composition according to claim 19 for use in a transdermal formulation.

23. A composition according to claim 22 for use as a transdermal patch.

24. The composition according to claim 13 wherein (S)-lomefloxacin or a pharmaceutically acceptable salt thereof, substantially free of its (R)- stereoisomer is administered together with a pharmaceutically acceptable carrier.