ANTI-VAGINITIS COMPOSITIONS WITH IMPROVED RELEASE AND ADHERENCE

Technical Field of the Invention The present invention relates to novel compositions for treatment of vaginal infections. The invention is particularly pertaining to anti-vaginitis compositions with improved release profile and superior adherence to mucosal surface of the vaginal cavity.

Background of the Invention

One of the problems associated with topically applied anti-vaginitis formulations is their short duration of action which, at least in part, is due to their limited retention at the mucosal surface of the vaginal cavity. The mucous coating is particularly susceptible to this problem due to its non-adherent nature and the fact this is rapidly replaced. A major problem in the delivery of drugs to a vaginal cavity is thus maintaining the active drug at the intended site of action for a sufficient period to achieve desired delivery of drug and effective treatment of the infectious condition.

Various gels are known for use in delivering drugs to body surfaces, including mucosal surfaces. Although these allow for a more uniform delivery of active, on warming to body temperature most gels have a tendency to lose their viscosity and adherence which leads to their displacement. The presence of natural bodily fluids also tends to result in their removal from the delivery site. Their limited retention reduces the therapeutic action of the active components thereby prolonging treatment periods and increasing the number and frequency of dosages required for clinical efficacy. Leakage of gels from vagina, is also undesirable for the patient.

Various medicaments in the form of vaginal tablets, pessaries and creams tailored for controlled release of drugs have been proposed, as for instance disclosed in WO 2005/087270 A1 , wherein the active principles are delivered by pharmaceutical vehicles including poloxamers that are used to confer in-situ gelling. Other ways of obtaining sustained release of drugs include use of micro-sponges, porous particles or using the lipophilic/hydrophilic properties of drugs in the vaginal route. Although the aforesaid ways and embodiments provide controlled release to a certain extent, the state of the art techniques suffer of a lack of sufficient adherence to the vaginal walls and mucosa rendering their retention time very limited. To be clinically effective, especially in combating trichomoniasis, it is necessary for patients to undergo a 7-day treatment in which one pessary is administered daily. The treatment period can be reduced to 3 days by doubling the daily dose to two pessaries per day. However, the acceptability of pessaries to patients is generally low which often means that the course of treatment is not completed. Since patients tend to experience an improvement in symptoms within the first 24 hours of treatment, this often leads to the situation in which the patient elects to discontinue treatment. This results in recurrence of the infection and, more significantly, development of antibiotic resistance.

Thermoreversible gels have been proposed for use in improving drug delivery to mucosal surfaces. These are liquid at room temperature but form a semi-solid when warmed to body temperature. For example, US 4,188,373 describes the use of Pluronic® poloxamers as thermally gelling polymers. Although these overcome some of the problems relating to the use of conventional gels, their bioadhesive force is weak which tends to result in detachment from the mucosal surface before treatment is complete. This is a particular problem in the vaginal cavity where the presence of vaginal fluids has a tendency to displace the gel. A general need thus still exists for improved formulations which are capable of adhering to vaginal surfaces. On the other hand, there still exists a need for such formulations which are also able to provide an extended release of a wide range of actives thereby minimising the frequency of application even under the flush effect of bodily fluids. We have now developed anti-vaginitis compositions having improved thermoreversible and bioadhesive properties in situ which address the problems associated with conventional formulations for use in treating body cavities and/or body surfaces, in particular those which have been proposed for application to mucosal membranes. Brief Description of the Figures

Figure 1 demonstrates a tensile testing to compare the bioadhesion of the formulation of Example 2 (RFA41 1 -15) with Universal Placebo base (RFA41 1 -46). Figure 2a shows drug release (whole) in μg from the formulation of Example 2 (RFA41 1 -15) through PVDF membrane.

Figure 2b shows drug release (diluted 10% with VFS) in μg from the formulation of Example 2 (RFA41 1 -15) through PVDF membrane.

Figure 3a shows drug release (whole) in % release from the formulation of Example 2 (RFA41 1 -15) through PVDF membrane. Figure 3b shows drug release (diluted 10% with VFS) in % release from the formulation of Example 2 (RFA41 1 -15) through PVDF membrane.

Figure 4a shows comparative drug release (whole) in μg from the formulation of Example 2 (RFA41 1 -15) through porcine vaginal tissue.

Figure 4b shows comparative drug release (diluted 10% with VFS) in μg from the formulation of Example 2 (RFA41 1 -15) through porcine vaginal tissue.

Figure 5a shows comparative drug release (whole) in % release from the formulation of Example 2 (RFA41 1 -15) through porcine vaginal tissue.

Figure 5b shows comparative drug release (diluted 10% with VFS) in % release from the formulation of Example 2 (RFA41 1 -15) through porcine vaginal tissue. Detailed Description of the Invention

Vaginal infections are conditions which are typically caused by mixed infection with Candida albicans, Trichomonas vaginalis and/or Gardnerella sp. The conventional compositions to treat these kind of conditions may be in the form of a pessary, gel, cream, tampon or foam containing the active medicaments, which however suffer of the drawbacks as per mentioned above.

Therefore, one of the objectives of the present invention is to provide anti-vaginitis compositions with thermoreversible gelling properties in order to control the release profile of the active materials. Thermoreversible vehicles as provided within novel compositions according to the present invention, following application to an internal or external body surface, undergo a thermoreversible transformation (sol-gel transition) on warming to body temperature thereby improving their retention at the target site. By appropriate selection of the active (or combination of actives), these also have the benefit that they continue to release the active (or actives) for an extended period of time, e.g. up to several days. As a result, the number and frequency of applications can be reduced and, in certain cases, a single dose (i.e. once only) treatment will suffice. A further advantage of the pharmaceutical vehicles which have been developed is their ability to tailor or 'tune' the release profile of one or more active agents which may be dispersed or otherwise dissolved therein. This is particularly beneficial where more than one active agent is to be delivered, the different actives having different degrees of solubility in the delivery vehicle. For example, a first active which is only slightly soluble or insoluble in the vehicle may exhibit a rapid or 'burst' release following delivery to the target site, whereas a second active which is more soluble may be released more slowly from the vehicle thereby providing an 'extended' release profile. The vehicles are thus able to function not only as highly effective carriers for active agents, but also as a "depot" from which these can be delivered over extended periods of time.

In one aspect, the invention provides a pharmaceutical composition suitable for treating a vaginal condition, said composition comprising:

a) at least one active agent effective against Candida spp. (more preferably Candida albicans), Trichomonas vaginalis and/or Gardnerella vaginalis in an extended release form,

b) a poloxamer mixture containing at least two poloxamers;

c) a fatty acid ester derived from a C ₈ to C ₂₂ saturated or unsaturated fatty acid; and d) a glycol ether. The pharmaceutical compositions in accordance with the invention are generally liquid or semi-solid at ambient temperature (i.e. below about 30 ^, preferably below about 25 'Ό) which means that these can be applied to the vaginal cavity by conventional means. At body temperature, these undergo a sol-gel transition to become viscous (or, in certain cases, more viscous) and to form a non-flowing gel which is capable of delivering the active agent (or active agents) as required for prolonged periods of time. They typically have a sol- gel transition temperature in the range of from about 25 to about 40 °C, preferably from about 25 to about 37 ^< €, e.g. around 35°C.

Preferably, the compositions will be viscous liquids, gels or creams at ambient temperature. The degree of viscosity of the compositions forms another important aspect of the present invention because of the objectives of obtaining better retention and bioadherence in the vaginal cavity. While advantageous viscosity values can majorly be attained by virtue of the poloxamers, these can vary widely and will depend on a number of factors such as temperature, pH, bioadhesive component(s), drug loading, etc. The formulations may range from thin liquids to gels; these will typically have viscosities in the range of from 1 ,000 to 500,000 cps at ambient temperature. The inventors report that, for vaginal conditions, the viscosity of the formulations will preferably lie in the range of from 80,000 to 200,000 cps, more preferably from 120,000 to 180,000 cps at ambient temperature (e.g. about 25 'Ό), and in the range 250,000 to 350,000 cps, more preferably from 270,000 to 300,000 cps in vaginal conditions (when measured using a Brookfield Viscometer with a Spindle RV-TF @ 10 rpm for 1 minute).

The thermoreversible gelling properties of the vehicles and compositions arise from the use of a mixture of poloxamers. Poloxamers are a family of ethylene oxide-propylene oxide block copolymers. They may also be referred to as copolymers of polyethylene oxide (PEO) and polypropylene oxide (PPO) and may be represented by the formula:

HO-(C ₂ H ₄ 0) _a (C ₃ H ₆ 0) _b (C ₂ H ₄ 0) _a -H where a and b denote the number of polyethylene oxide or polypropylene oxide units, respectively (i.e. the PEO and PPO segments). The values of a and b will vary depending on the particular grade of poloxamer. In general, each a is about 10 to about 150, preferably from 12 to 101 , and b is about 20 to about 60, preferably from 20 to 56.

Ethylene oxide-propylene oxide block copolymers in which the number of polyethylene oxide units is at least about 50% of the number of units in the molecule are preferred for use in the invention, in particular those in which at least about 60%, more preferably at least about 70% of the units are polyethylene oxide. Those having approximately 70% or approximately 80% polyethylene oxide units are especially preferred. Copolymers having an average molecular weight of from about 5,000 to about 15,500, preferably from about 7,000 to about 15,500, yet more preferably from about 7,500 to about 15,000 may be used. Suitable poloxamers for use in the invention are those sold under the tradenames Pluronic® and Lutrol® by BASF. Preferred grades of poloxamers include Poloxamer 407, Poloxamer 188, Poloxamer 124, Poloxamer 237, Poloxamer 338 and mixtures thereof, the specifications of which are detailed below:

The poloxamer mixture contains at least two poloxamer polymers, preferably first and second poloxamers. Preferably the first poloxamer is selected from Poloxamers 407, 124, 237 and 338. More preferably, the first poloxamer is Poloxamer 407. Preferably, the second poloxamer is selected from Poloxamers 188, 124, 237 and 338. More preferably, the second poloxamer is Poloxamer 188. Particularly preferred for use in the invention are Poloxamer 407 (available from BASF as Pluronic® F127) and Poloxamer 188 (available from BASF as Pluronic® F68). It is noted that this particular selection of the poloxamers enables to adjust gelling temperature of the composition to around body temperature, and more specifically to around 25-37°C, and most preferably 33-36°C that is ideal in vaginal conditions.

Where first and second poloxamer polymers are present, these may be present in a weight ratio of about 6:1 to about 1 :6, more preferably about 2:1 to about 1 :2, e.g. about 1 .5:1 to 1 :1 .5.

The total amount of the poloxamer polymers in the vehicles and compositions herein described will generally be in the range of from 1 to 30 wt.%, preferably 20 to 30 wt.%, yet more preferably from 25 to 30 wt.%. It is generally preferred that the total amount will not exceed 30 wt.%.

The thermoreversible character of the formulation imparts a low viscosity at ambient temperature. Generally, this will thus be in liquid or semi-solid form at ambient temperature and viscous at body temperature. Administration of the formulation in liquid or semi-solid form permits ready and uniform application and distribution on the desired body surface (whether external or internal). On warming to body temperature, the more viscous form permits improved adhesion by limiting the flow of the product. The superior bioadhesion effect of the compositions herein described is achieved using a combination of a fatty acid ester derived from a C ₈ to C ₂₂ saturated or unsaturated fatty acid, a glycol ether and a poloxamer mixture. This specific combination notably increases bioadherence of the pharmaceutical vehicle or composition in vaginal cavity even in existence of excessive mucosal media. With combination of the thermogelling properties by virtue of the poloxamers, release profile of pharmaceuticals are considerably improved as demonstrated in the examples. By combined effect of the poloxamers along with fatty acid esters and glycol ether, release profile of anti-vaginitis compositions goes beyond the expected values by virtue of the improved retention time in vaginal walls. In other terms, flush/leak effect due to mucosal and bodily fluids is eliminated for longer durations.

Examples of saturated fatty acids which may be used to form the fatty acid esters according to the invention include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid and behenic acid. Unsaturated fatty acids which may be used include palmitoleic acid, oleic acid, linoleic acid, linolenic acid and arachidonic acid. Preferred for use in the invention are unsaturated fatty acids, in particular oleic acid.

Particularly suitable for use in the invention are fatty acid esters of polyhydric alcohols. In such cases, the hydroxy-containing component may be partially or fully esterified with one or more fatty acid components. Suitable polyhydric alcohols include glycerol, 1 ,2- propanediol and 1 ,3-propanediol. Fatty acid esters formed from polyhydric alcohols may be mono-, di- or tri-valent. Those which comprise a single ester group (i.e. monoesters) are preferred for use according to the invention. In the case of di- or tri-esters, the fatty acid components may be the same or different. In a preferred aspect of the invention, the polyhydric alcohol is glycerol.

Examples of fatty acid esters for use in the invention in which the hydroxy-containing component is a polyhydric alcohol are glyceryl monooleate, glyceryl monolinoleate, glyceryl monolinolenate, glyceryl monostearate, glyceryl palmitostearate, and combinations thereof. Particularly preferred is glyceryl monooleate (monoolein). The fatty acid esters for use according the invention are either commercially available or may readily be synthesized using esterification methods well known in the art. Many of the commercially available fatty acid esters are not 100% pure, but tend to contain more than about 80%, typically more than about 90% by weight of the desired fatty acid ester. Other components of the mixtures may include other fatty acid esters and other fatty acids.

Glyceryl monooleate (GMO) is available commercially from various sources, e.g. as Myverol from Kerry Bio-Science. Typically, GMO is supplied as a mixture of glycerides of oleic acid (primarily) and other fatty acids. GMO products having a monoester content of not less than 90% are preferred for use in the invention. Typically, the melting point of the mixture will lie in the range 35 to 37 ^< Ό and the water content will be less than 1 .0%.

The amount of fatty acid ester present in the compositions herein described will generally be in the range of from about 0.1 to about 1 wt.%. More preferably, this will be present in an amount of less than 0.5 wt.%, e.g. in an amount in the range 0.1 to 0.3 wt.%.

Suitable glycol ethers for use in the invention include ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, propylene glycol monoethyl ether and dipropylene glycol monoethyl ether. Although a mixture of glycol ethers may be used, a single glycol ether is preferred. Particularly preferred is diethylene glycol monoethyl ether or DGME (also known as ethoxydiglycol). DGME is a pharmaceutical grade transparent liquid (MW 134.2) with unique solubilizing properties. It has the ability not only to solubilize both hydrophilic and hydrophobic materials, but also has penetration enhancing properties. It is marketed as a highly purified liquid under the tradename Transcutol® (Gattefosse s.a., Saint Pres Cedex, France).

The amount of glycol ether present in the compositions herein described will generally be in the range of from about 0.05 to about 1 wt.%, preferably from 0.1 to 0.6 wt.%, e.g. about 0.5 wt.%.

The bioadhesive character of the formulation improves the contact between the active or combination of actives and the body surface. This results in improved retention and increased therapeutic efficacy, thereby reducing the number of applications and the duration of treatment required. The bioadhesive nature of the formulation further limits the flow of the product once in situ. Other natural or synthetic bioadhesive enhancing agents may also be present in the vehicles and compositions herein described in addition to the fatty acid ester and glycol ether components. Examples of such agents are disclosed in WO 2005/087270, the entire content of which is hereby incorporated by reference. Particularly suitable are poly(carboxylic acid-containing) based polymers, such as poly(acrylic, maleic, itaconic, citraconic, hydroxyethyl methacrylic, methoxyethyl methacrylic, methoxyethoxyethyl methacrylic or methacrylic) acid which have strong hydrogen-bonding groups, or derivatives thereof such as salts and esters. Appropriate bioadhesives having this form are available commercially (e.g. from Goodrich) as Polycarbophil, e.g. Noveon AA-1 , Carbomer (Carbopol), e.g. Carbopol EX165, EX214, 434, 910, 934, 934P, 940, 941 , 951 , 971 , 974P, 980, 981 , 1342 and 1382.

Other bioadhesives which may be present include cellulose derivatives such as methyl cellulose, ethyl cellulose, methylethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl ethyl cellulose, carboxymethyl cellulose, hydroxypropylmethyl cellulose or cellulose esters or ethers or derivatives or salts thereof, e.g. hydroxypropyl methyl cellulose-E15 (HPMC E-15) or sodium carboxymethyl cellulose-H (Sodium CMC-H). Combinations of two or more cellulose derivatives may also be employed, for example HPMC E-15 and Sodium CMC-H.

Other naturally occurring or synthetic polymers may also be used for their bioadhesive properties, e.g. acacia gums, xanthan gum, guar gum, locust bean gum, tragacanth gums, karaya gum, ghatti gum, cholla gum, psillium seed gum and gum arabic; clays such as manomorillonite clays, e.g. Veegum, attapulgite clay; polysaccharides such as dextran, pectin, amylopectin, agar, carrageenan, mannan or polygalactonic acid or starches such as hydroxypropyl starch or carboxymethyl starch; lipophilic formulations containing polysaccharides, e.g. Orabase (Bristol Myers Squibb); carbohydrates such as polysubstituted with groups such as sulphate, phosphate, sulphonate or phosphonate, e.g. sucrose octasulphate; polypeptides such as casein, gluten, gelatin, fibrin glue; chitosans which are a natural polycationic copolymer consisting of glycosamine and N- actylglucosamine units (e.g. the chloride salt, lactate or glutamate thereof) or carboxymethyl chitin; glycosaminoglycans such as hyaluronic acid and its derivatives; metals or water soluble salts of alginic acid such as sodium alginate or magnesium alginate; schleroglucan; adhesives containing bismuth oxide or aluminium oxide; atherocollagen; polyvinyl polymers such as polyvinyl alcohols, polyvinylmethyl ethers, polyvinylpyrrolidone, polycarboxylated vinyl polymers (such as polyacrylic acid); polysiloxanes; polyethers; polyalkylene oxides and glycols, e.g. polyethylene oxides and glycols; polyalkoxys and polyacrylamides and derivatives and salts thereof; polyglycolic and polylactic acid homopolymers and copolymers; glycolide and lactide copolymers, e.g. poly-L-(lactide co-glycolide); and polymeric emulsifiers, e.g. Pemulen™ polymeric emulsifiers which are high molecular weight, cross-linked copolymers of acrylic acid and a hydrophobic comonomer.

Where additional bioadhesive components are present, these will preferably be selected from: poly(carboxylic acid-containing) based polymers; tragacanth gums; pectin; carrageenan; chitosan; starches; gelatin; hyaluronic acid and derivatives thereof; cellulose derivatives; polyethylene glycols; and polymeric emulsifiers. Poly(carboxylic acid- containing) based polymers such as polyacrylic acid are especially preferred.

Where any other bioadhesive enhancing agents are present, these will typically be present in the compositions in an amount in the range of from about 0.1 to about 1 wt.%, preferably from 0.1 to 0.5 wt.%, e.g. 0.1 to 0.3 wt.%.

Other conventional components may also be included in the vehicles and compositions herein described, for example, preservatives (e.g. propylparaben, methylparaben, phenoxyethanol, etc.), antioxidants (e.g. BHT or BHA), pH adjusters (e.g. lactic acid, etc.) anti-foaming agents (e.g. simethicone emulsion), neutralizing agents, dispersing agents, penetration enhancers, solubilizers, emulsifiers, etc. These components may each be provided in an amount ranging from about 0.1 to about 15 wt.%, preferably in an amount from 0.1 to 10 wt.%, more preferably from 0.1 to 5 wt.%, e.g. from 0.1 to 1 wt.%.

Anti-foaming agents may be used to suppress foaming during manufacture of the vehicles and compositions. Particularly suitable for use in this regard are simethicone-containing emulsions, e.g. Simethicone Emulsion, USP which is a non-ionic emulsion containing 30 wt.% simethicone.

Solubilizers which may be present include polyvinylpyrrolidones such as plasdone povidone which is a synthetic water-soluble homopolymer of N-vinyl-2-pyrrolidone. It has adhesive, film forming and surface active properties and may be used to enhance the solubility and bioavailability of poorly soluble drugs. In certain cases, it may also function to inhibit crystal growth of an active agent. Inorganic bases, such as sodium hydroxide, may be present to act as neutralizing agents. Other compounds suitable for this purpose include potassium hydroxide, triethanolaminine, aminomethyl propanol, trisamino- and tetrahydroxypropyl ethylenediamine. Amino acids such as β-alanine and lysine can also be used for neutralization and viscosity modification. Sodium hydroxide may also function as a pH adjuster.

Dispersing agents which may be present include propylene glycol. This is also known for its emollient, humectant and viscosity modifier properties. Alternatives to propylene glycol include glycerine, sorbitol, butylene glycol, etc.

Agents may also be present to function as pH adjusters in the compositions according to the present invention. These aid in retaining the physical and chemical stability of the formulations. Suitable agents include lactic acid which is also particularly beneficial in the context of a product for application to the vaginal mucosa since it can help to mimic the natural vaginal microflora; normal microflora are primarily lactobacilli which produce sufficient lactic acid to acidify vaginal secretions to a pH in the range of 3.5 to 4.5. This value is maintained by the lactobacilli which convert glycogen from exfoliated epithelial cells into lactic acid. The various components of the compositions will generally be admixed in an aqueous system comprising water and a solvent. The solvent should be pharmaceutically acceptable and may be, for example, a Ci _-6 alcohol, N-methylpyrrolidone, a glycol or a glycol ether (e.g. propylene glycol, 1 ,3-butylene glycol, dipropylene glycol, diethylene glycol or diethylene glycol monoethyl ether (DGME), or an ether (e.g. diethyl ether). Mixtures of any of these solvents may also be used. A preferred solvent system is that containing water and DGME.

At ambient temperature, the compositions herein described may take the form of a liquid, gel, paste, cream, pessary, viscous solution or dispersion. A pharmaceutical composition in the form of a pessary refers to a solid or semi-solid composition having a similar shape as conventional pessaries, but having its own release profile without needing a capsule or plastic body for storing a medicament. Preferably, these take the form of a liquid, cream or gel which is easy to apply. Particularly preferred are compositions which are in the form of a cream or viscous liquid (e.g. gel). When brought into contact with vaginal area or cavity in vivo, the compositions undergo a phase transition whereby to form a highly effective drug delivery system from which the active agent (or active agents) may be delivered. In accordance with present invention, these form a depot from which the active or actives may be delivered over an extended period of time.

Methods for making the pharmaceutical vehicles and compositions herein described also form part of the invention. These may be made by methods which involve dissolving or dispersing the mixture of poloxamers in a solvent or solvent system at low temperature, e.g. at a temperature below about 25°C, preferably in the range 10-15°C, more preferably in the range 5-10°C. The fatty acid ester may similarly be dissolved or dispersed in a solvent or solvent system prior to admixing with the poloxamer mixture. The glycol ester may then be added to the resulting mixture. In preparing the compositions, the active agent (or agents) may subsequently be added to the final mixture or, alternatively, these may be dispersed or dissolved in any of the components of the composition during its preparation.

In a further aspect, the invention thus provides a method for the preparation of the pharmaceutical compositions herein described, said method comprising forming a mixture comprising: a) a poloxamer mixture containing at least two poloxamers; b) a fatty acid ester derived from a C ₈ to C ₂ 2 saturated or unsaturated fatty acid; c) a glycol ether; and d) at least one biocompatible solvent or solvent system; and dissolving or dispersing at least one active agent effective against Candida spp., Trichomonas vaginalis and/or Gardnerella sp. in the resulting mixture or in at least one of components a) to d) prior to forming said mixture, wherein said active agent(s) is provided in an extended release form .

Drugs which are particularly suitable for administration in the compositions of the invention include those within the following classes: anti-infectives, anti-inflammatories, analgesics and anaesthetics. Most preferred are anti-infectives, such as anti-fungals, anti-bacterials, anti-protozoals, etc.

The compositions herein described that are suitable for the treatment and/or prevention of primary and/or secondary vaginal infections, e.g. mixed vaginal infections such as those associated with acute and recurrent vulvovaginal candidiasis, bacterial vaginosis and trichomonal vaginitis and/or their causative agents. Vaginal infections due to group B and D streptococcus and the like, infections due to microorganisms causing vulvitis and vulvovaginitis, and other vaginal infections (e.g. atrophic vaginitis, allergic or irritant vulvo vaginitis, genital psoriasis (with or without clinically relevant infection), vulvitis due to Lichen sclerosis, etc.) may also be usefully treated using the compositions herein described. They also find use in treatment of any associated symptoms such as inflammation, irritation and itching.

Vaginitis is most often caused by infection with Candida albicans, Trichomonas vaginalis or Gardnerella sp, either singly or mixed. Certain derivatives of imidazole and nitroimidazole are known to have anti-fungal, anti-bacterial and/or anti-protozoal activity and are often used to treat such conditions. Examples of such drugs include miconazole, clotrimazole and metronidazole. Other types of drugs used in treating vaginal infections include nitrofurfuryl derivatives and various antibiotics.

Examples of suitable triazole compounds for use in the invention include terconazole, itraconazole, fluconazole, voriconazole, ravuconazole, posaconazole, hexaconazole and fosfluconazole. Of these, terconazole is preferred. It has a particularly broad spectrum of activity and has been shown to be effective against Candida spp., such as Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis, Candida pseudotropicalis, Candida stellatoidea and Candida lusitaniae. Terconazole has the further advantage that this does not kill useful lactobacillus microorganisms which form part of a healthy vaginal flora.

Anti-fungal compounds suitable for use in the compositions according to the invention include griseofulvin, nystatin, polymixin B, terbinafin and atovaquone (Meprone). Preferred anti-fungals are the imidazoles and pharmaceutically acceptable salts thereof. Suitable fungicidally active imidazole compounds include those active against Candida albicans such as tioconazole, butoconazole, miconazole (e.g. miconazole nitrate), ketoconazole, clotrimazole, isoconazole, seperconazole, econazole, oxiconazole, sulconazole, azanidazole, neticonazole, clomidazole, croconazole, eberconazole, flutrimazole, bifonazole and spectazole. Particularly preferred are tioconazole or butoconazole.

Other anti-fungal agents which may be used include the echinocandins (β-glucan synthase inhibitors) such as Anidulafungin, Caspofungin and Micafungin; allylamines (squalene monooxygenase inhibitors) such as Amorolfine; and benzimidazoles such as thiabendazole. Anti-protozoal agents for use in the compositions of the invention include Paromomycin, Diclazuril (Clinacox) and Letrazuril. Preferred anti-protozoals are those which are known to be active against Trichomonas vaginalis. Particularly preferred anti-trichomonal drugs are those which also have anti-bacterial activity, in particular against Gardnerella sp and other pathogens capable of causing vaginitis, e.g. anaerobic bacteria, group B and D streptococcus and/or pathogens causing other primary or secondary vaginal/genital infections. Examples of suitable anti-protozoal agents include tinidazole, metronidazole, ornidazole, secnidazole and nimorazole. Tinidazole is particularly preferred. Anti-bacterial agents suitable for use in the invention include those which are active against Gardnerella sp and other pathogens capable of causing vaginitis, e.g. anaerobic bacteria, group B and D streptococcus and/or pathogens causing other primary or secondary vaginal/genital infections. Broad spectrum antibiotics such as pivampicillin or clindamycin may usefully be included. Other suitable anti-bacterial agents include chlorquinaldol, diiodohydroxyquinoline, chloramphenicole and spiramycin (rovamycin).

In the treatment of vaginal infections, particularly those of mixed origin, combinations of actives may usefully be used. Particularly preferred for use in the invention is the combination of tinidazole and tioconazole.

It may also be advantageous to use one or more local anaesthetics in the compositions of the invention in order to alleviate the soreness associated with vaginitis. Examples of suitable anaesthetics include aptocaine, bupivacaine, butanilicaine, carticaine, cinchocaine, clibucaine, ethyl parapiperidinoacetyl-aminobenzoate, etidocaine, lidocaine (lignocaine), mepivacaine, oxethazaine, prilocaine, pyrrocaine, ropivacaine, tolycaine, vadocaine, benzocaine, pramoxine and mixtures thereof. The anaesthetic may also be used in the form of a salt, optionally in combination with the base form whereby to achieve extended release of the anaesthetic. The local anaesthetic may be used in an amount of 0.1 -10.0% by weight, preferably 1 .0- 7.0%. The local anaesthetic is preferably lidocaine and may be used in the form of its free base (for example in an amount of 1 .0-3.0%, by weight, preferably about 1 .5%) or a salt such as its hydrochloride, for example 1 .5-4.0% by weight, preferably about 2%. The use of the anaesthetic at these low concentrations results in the compositions being well tolerated. One or more wound healing or skin protectant agents may also be present in the compositions. These may be selected from demulcents, absorbents and emollients and include dimethicone (demulcent), allantoin (absorbent), sucralfate and glycerin (absorbent, demulcent and emollient). Examples of other suitable emollients include cocoa butter, white petrolatum and shark liver oil. Dimethicone has been found to be particularly advantageous in facilitating healing of the vaginal mucosa and is therefore particularly preferred for use in the compositions herein described.

In order to counter the inflammation and itching associated with vaginitis, it may be beneficial to include an anti-inflammatory and/or anti-pruritic agent such as hydrocortisone, hydrocortisone acetate, methylprednisolone acepronate, betamethasone valerate, or the like, or a weak topical steroid and/or plant-derived anti-inflammatory bioactive such as bisabolol or chamomille. Boric acid and/or lactic acid may also advantageously be included as a further active ingredient. The compositions may also include chlorophyll as a deodorant. Other active components which may be present in any composition intended for application to the vaginal mucosa include estrogens such as estriol, conjugated estrogens and promestrien.

Anti-viral agents such as acyclovir, penciclovir, trifluridine, afovirsen, arildone, brivudine, I- docosanol, edoxudine, ganciclovir, idoxuridine, moroxydine, tromantadine and valacyclovir may also be present.

Conventional microbicides capable of preventing HIV and/or other sexually transmitted infections may also be included in the compositions herein described when these are intended for application to the vaginal mucosa. Examples of such agents include those which disrupt or otherwise disable HIV, such as surfactants, e.g. menfegol, benzalkonium chloride, docosanol, C31 G (Savvy, nonoxynol-9, sodium cholate), polybiguanides, sodium dodecyl sulphate; antibiotics, e.g. gramicidin, magainins, defensins, protegrins; acidifying agents, e.g. Buffer Gel, Acidform, Lactobacillus crispatus; oxidising agents, e.g. chlorhexidine, povidone iodine, hydrogen peroxide/peroxidase gel; antibodies, e.g. anti-HIV antibodies; long-chain anionic polymers, e.g. cellulose acetate phthalate; reverse transcriptase inhibitors, e.g. UC-781 , loviride, tenofovir; agents which block HIV attachment/fusion, such as long-chain anionic polymers, e.g. dextrin-2-sulphate, naphtalene sulphonate polymer (Pro 2000), carrageenan, polystyrene sulphonate, cellulose sulphate, cellulose acetate phthalate, polymeric dimandelic acid ether (SAMMA); dendrimers, e.g. SPL7013, HIV-binding peptides/proteins, e.g. cyanovirin; T-20; lipid membrane modifiers, e.g. beta-cyclodextrin; anti-CD4 antibodies, e.g. B-12; agents which prevent intracellular HIV replication (e.g. nepirapine 16); reverse transcriptase inhibitors (e.g. UC-781 , loviride, tenofovir); and plant products (e.g. Praneem, gossypol, pokeweed antiviral protein), etc. Other active agents which may be provided in the compositions herein described include bromochlorosalicylanilide, methylrosaniline, tribromometacresol, polynoxylin, chlorophetanol, chlorophenesin, ticlatone, sulbentine, ethyl hydroxybenzoate, haloprogin, piroctone olamine, dimazole, tolciclate, sodium thiosulfate, potassium iodide, dapsone, tea tree oil, citronella oil, lemon grass, orange oil, patchouli and lemon myrtle.

In a preferred embodiment of the invention, the compositions will comprise at least first and second actives which are both anti-infectives. For example, the first active may be an antifungal agent, e.g. tioconazole, and the second active may be an anti-protozoal agent, e.g. tinidazole.

The quantity of active (or actives) may be readily determined by those skilled in the art and will depend on several factors, including the nature of the active(s) and of any other non- active components, the condition to be treated, and the duration of treatment, etc. In general, the actives may be used in amounts of from about 0.01 to 25% by weight, preferably from 1 to 20% by weight, more preferably from 5 to 15% by weight.

The various drug substances which are described herein vary in their hydrophilic and hydrophobic characteristics and this will influence their release profile once the compositions have been delivered to the intended site of treatment. As will be described herein, appropriate selection of the drug or combination of drug substances which vary in their hydrophobic/hydrophilic nature enables the drug delivery profile of the compositions to be precisely tailored to provide the desired release characteristics.

In a preferred embodiment of the invention, the compositions herein described are adapted for the delivery of a combination of active drug substances which differ in their hydrophobic/hydrophilic properties.

Hydrophilic drug substances are those which have a tendency to interact with or be dissolved by water and other polar substances. In contrast, hydrophobic drug substances tend to be non-polar and prefer other neutral molecules and non-polar solvents; these are therefore poorly miscible or non-soluble in hydrophilic solvents such as water. As used herein, the term "hydrophilic" is generally used to refer to drug substances which have a solubility in water excess of 1 wt.% under ambient conditions. Those drug substances which have a solubility in water of less than 0.1 wt.% under the same conditions are generally considered to be "hydrophobic".

The compositions may include a first active agent and a second active agent, preferably a first active agent which is provided in a form which is capable of rapid release and a second active agent which is provided in a form which is capable of extended release. Following application to a body cavity or surface, the first active agent may be in a form adapted for release over a period of from 1 hour to 12 hours and the second active agent may be in a form adapted for release over a period of from 12 hours to 3 days. Preferably, the release of the second active will continue for a period of from 12 hours to 7 days after the end of the release period of the first active agent.

Non-limiting examples of hydrophilic and hydrophobic actives which may be provided in the various formulations herein described are set out in Table 1 . In respect of the vaginal condition given, any of the actives listed may be used alone or, alternatively, in combination. Combinations of hydrophilic and hydrophobic actives are particularly preferred.

Table 1 - Route: Vaginal

Condition Hydrophilic Active Hydrophobic Active

Vaginal conditions, tioconazole Tinidazole

e.g. vaginitis

Sulfanilamide miconazole (e.g.

miconazole nitrate)

Nitrofurazone terconazole

Nitrofurantoin fluconazole

paromomycin sulfate ketoconazole

chloramphenicole itraconazole

sodium succinate

clotrimazole

butoconazole (e.g.

butonconazole nitrate)

isoconazole superconazole

econazole

oxiconazole

sulconazole

ornidazole

secnidazole

nimorazole

griseofulvin

Nystatin

polymixin B

pivampicillin

clindamycin

spiramycin

terbinafin

(e.g. terbinafin HCI)

atavaquone

paromomycin

diclazuril

Letrazuril

chloroquinaldol

diiodohydroxyquinoline

chloramphenicole

Any of the agents described herein may also be used in the form of their pharmaceutically acceptable salts. When used to deliver drugs vaginally, the compositions may be administered using a suitable applicator which may be disposable. For example, where the compositions are provided in the form of a liquid or cream, a syringe may be used to deliver this to the desired body cavity. The syringe may be provided with an appropriate delivery tube or needle.

Kits comprising a composition as herein described and an applicator adapted for delivery of the composition to a body cavity and/or body surface form a further aspect of the invention.

A device (e.g. a syringe) pre-loaded with at least one dose of a composition as herein described also forms a further aspect of the invention. Any such device will generally be adapted to deliver one or more doses of the product in a highly uniform manner. Typically, a single unit dose may comprise from about 1 to about 10 grams or mis of said composition, preferably from about 2 to about 7 grams or mis, e.g. from about 3 to about 5 grams or mis. Examples of suitable delivery devices include those known in the delivery of vaginal creams, such as that used in the product Gynazole-1® (available from Ther-Rx Corporation).

For use in topical application, the compositions may be packaged in any conventional delivery means such as tubes, containers provided with an actuated plunger, etc.

Due to the thermoreversible nature of the formulations herein described, these will ideally be packaged with instructions for storage below room temperature, e.g. in a refrigerator. Alternatively, or in addition, these may be housed in external packaging which provides insulation from any external temperature source.

The invention will now be described by way of the following non-limiting Examples: Example 1 - Formulation A thermo-reversible bioadhesive formulation having the following composition was prepared:

Phase D

Mucoadhesive Composition Phase

Distilled water 0.17

Myverol 18-99k Glyceryl monooleate (supplied by Kerry 0.24

Bio-Science)

Transcutol Purified diethylene glycol monoethyl ether 0.09

EP, and USP-NF (supplied by Gattefosse)

Phase E

Mucoadhesive Antifoaming and coupling

enhancement Phase

Transcutol P Purified diethylene glycol monoethyl ether 0.50

EP, and USP-NF (supplied by Gattefosse)

Dow Corning Q7-2587 30% Simethicone 30% Simethicone emulsion USP 1 .00 emulsion, USP (containing 30% simethicone USP,

stearate emulsifiers, sorbic acid, benzoic

acid, thickeners and water, supplied by

Dow Corning)

Phase F

Actives pre- dispersion Phase

Propylene glycol, USP Propylene glycol, USP 10.00

Plasdone K-1 7, PVP Polyvinylpyrrolidone (Povidone, USP, 3.00

supplied by ISP)

Tinidazole base micronized, EP Tinidazole base micronized, EP (supplied 3.00

by Selectchemie AG)

Tioconazole base micronized, PH, Eu Tioconazole base micronized, PH, Eu 2.00

(supplied by Selectchemie AG)

Phase G

Preservatives Phase

Methylparaben, NF Methylparaben Ph Eur, BP, NF, FCC, 0.10

E218

Propylparaben, Ph Eur, BP, NF, FCC, E Propylparaben, Ph Eur, BP, NF, FCC, E 0.02 216 216

Phenoxetol, Low Phenol Phenoxyethanol (supplied by Clariant 0.30

Corporation)

Phase H

pH Balancing Phase

Lactic Acid, 88 % USP-FCC Lactic acid, 88 % USP-FCC 0.06

(adjusting pH from 5.5 to 7.00, supplied by

Mallinckrodt)

Total: 100.00

Preparation of Phase D:

Phase D of the composition having the following composition was prepared as outlined below:

INGREDIENTS INCI.NAME w/w %

Phase A

Thermogelling Phase

Distilled water Distilled water 34.80 Phase B Bioadhesive Enhancer

Phase

Myverol 1 8-99 k Glyceryl monooleate (supplied by 47.20

Kerry Bio-Science)

Phase C

Polycarbophil Neutralization Phase

Transcutol P Purified diethylene glycol monoethyl 18.00

ether EP, and USP-NF (supplied by

Gattefosse)

Total:

100.00

The Phase A component was weighed into a suitable sized container and a moderate mechanical mixing was initiated. Heating of the Main Batch to 75-80 °C was initiated. In a separate vessel Phase B (Main Batch) was mixed and heated to 75-80 °C. Once both (A and B) phases were at 75-80 °C, a moderate to vigorous mechanical mixing was applied and very slowly Phase A was added into Phase B. The temperature and mixing conditions were maintained for an additional 20 to 30 minutes (during which time the container was covered in order to avoid loss of water through evaporation). Mixing was maintained at a temperature of 75-80 °C, and very slowly Phase C was added into the Main Batch. Once a uniform mixture was obtained, the mechanical mixing speed was decreased and the mixture allowed to cool to ambient temperature to provide the final product as a slightly yellow viscous fluid having a viscosity of 2,000 cps (measured using Brookfield Viscosometer/Spindle RV-Sp#4 at 10 rpm for 1 min). 0.50 % w/w of the product was provided as Phase D (Mucoadhesive Composition Phase) in the final composition.

Preparation of final composition: 1 . The water and propylene glycol components of Phase A were weighed into a suitable sized container and a slow to moderate mechanical mixing was initiated. Cooling of the mixture to 10-15°C, preferably between 5-10° was achieved by placing the container into a water bath (containing ice and water).

2. Once the temperature of the Phase A ingredients was between 10-15 °C, the Pluronic F 68 NF Prill was slowly sprinkled in with slow to moderate mechanical mixing (avoiding foam formation) until a clear solution was obtained. When a clear, lump-free solution was observed, the Pluronic F127 NF Prill was slowly added and mixed until the solids were in solution and/or a lump-free mixture was obtained. 3. The water component of Phase B was weighed out into a separate container and using a propeller or marine type impeller (to achieve moderate to vigorous mechanical motion) the Noveon AA1 Polycarbophil was sprinkled in. The resulting mixture was mixed until a homogeneous lump-free dispersion was obtained.

4. After obtaining a homogeneous Phase B dispersion (no lumps nor "fish-eyes" are observed at this point), the mixture was added into the Main Batch (Phase A mixture) with slow to moderate mixing and maintaining the temperature conditions ( ^" Ι Ο-Ι δ'Ό). Further mixing was carried out to achieve uniformity.

5. Once a homogeneous Main Batch mixture was obtained, Phase C (sodium hydroxide, 20% solution) was added and mixed to uniformity, whilst maintaining the low temperature conditions.

6. Phase D (0.50 % w/w) was then very slowly added into the Main Batch at 10-15°C and mixed to uniformity.

7. Once a homogeneous mixture was obtained, the Phase E ingredients we added very slowly into the Main Batch (one at a time): Transcutol then Dow Corning Q7-2587 30%

Simethicone emulsion, USP. A low mechanical mixing speed was maintained at low temperature conditions, preferably at 5-10°C, until a very uniform mixture was obtained.

8. The propylene glycol, USP component of Phase F was added to a stainless steel kettle equipped with a side-sweep mixer and Lightning mixer and the Plasdone K-17 component slowly sprinkled. Mixing was continued until a clear solution formed. The remainder of the Phase F ingredients (active components) were then added: Tinidazole Base, Micronized, EP and Tioconazole Base, Micronized, PH Eur. Mixing was maintained at ambient temperature conditions until a homogeneous-off white dispersion was obtained.

9. When a homogeneous Phase F dispersion was observed, this was very slowly added into the Main Batch. Slow to moderate mechanical mixing and low temperature conditions (at 10-15°C, preferably between 5-10°C) were maintained and the composition mixed to uniformity.

10. One at a time the various Phase G ingredients were added: Methylparaben, NF; Propylparaben, NF; and Phenoxyethanol and the composition mixed to uniformity whilst maintaining the low temperature conditions at 10-15°C, preferably between 5-10°C.

1 1 . The Phase H ingredient (lactic acid, 88 % USP-FCC) was added. Mixing was maintained under low temperature conditions to obtain a uniform mixture. Under slow to moderate mechanical mixing, the Main Batch was then warmed to 20-25^. 12. The resulting product was a smooth, off-white cream having a pH of 6.8 and a viscosity of 100,000 cps (measured using Brookfield Viscosometer/Spindle RV-TF at 10 rpm for 1 min). Viscosity at 35-40 will be 30 to 60% higher due to thermoreversible effect. Example 2 - Formulation

A thermo-reversible bioadhesive composition having the following composition was prepared:

Tinidazole base micronized, EP Tinidazole base micronized, EP (supplied 9.00

by Selectchemie AG)

Tioconazole Base Micronized, PH, Tioconazole base micronized, PH, Eu 6.00

Eu (supplied by Selectchemie AG)

Phase G

Preservatives Phase

Methylparaben, NF Methylparaben Ph Eur, BP, NF, FCC, E218 0.10

Propylparaben, Ph Eur, BP, NF, Propylparaben, Ph Eur, BP, NF, FCC, E 216 0.02

FCC, E 216

Phenoxetol, Low Phenol Phenoxyethanol (supplied by Clariant 0.30

Corporation)

Phase H

pH Balancing Phase

Lactic Acid, 88% USP-FCC Lactic acid, 88% USP-FCC 0.06

(adjusting pH from 5.5 to 7.00, supplied by

Mallinckrodt)

Total: 100.00

Preparation:

The composition was prepared analogously to Example 1 . The resulting product was a smooth, off-white cream having a pH of 6.4 and a viscosity of 160,000 cps (measured using Brookfield Viscosometer/Spindle RV-TF at 10 rpm for 1 min). Viscosity at 35-40°C will be 30 to 60% higher due to thermoreversible effect.

Example 3 - Bioadhesive properties

A study was carried out to compare the bioadhesive strength of the formulation of Example 2 to that of Universal placebo gel.

The Universal placebo gel had the following composition:

Component w/w %

Hydroxyethyl cellulose 3.0

(thickening agent)

Glycerin (wetting agent) 5.0%

Methylparaben (preservative) 0.15%

Propylparaben (preservative) 0.05%

Distilled water, part 1 (solvent) 54.0%

Sodium chloride 0.03%

10% NaOH (pH adjuster) As needed

10% HCI (pH adjuster) As needed

Distilled water, part 2 (solvent) q.s. to 100 % Method for preparing Universal placebo gel:

1 . The appropriate amount of distilled water (part 1 ) was weighted into a container and the appropriate amount of sodium chloride was added.

2. The appropriate amount of glycerin was weighed into a beaker and heated to 65 'Ό. 3. The appropriate amounts of methylparaben and propylparaben were weighed into the small beaker and mixed until all solids had dissolved.

4. The mixture was cooled to <35°C, the HEC added and mixed until a homogeneous mixture was achieved.

5. With continuous propeller mixing, the mix from step 4 was added to that from step 1 . Mixing was continued until a homogeneous gel was formed.

6. pH was adjusted to 4.5±0.3 by adding the appropriate pH adjustment component. The net weight of the mixture was recorded.

7. The final portion of distilled water was calculated and, with continuous mixing and side scraping, added. Mixing continued until a homogeneous system was achieved.

8. The resulting gel was covered and allowed to equilibrate at room temperature overnight. pH was then measured and, if necessary, adjusted to 4.5±0.3.

Method:

Tensile testing was performed on Instron 3342 equipped with a 0.1 -10 N load cell. The assembly consisted of a movable measuring probe connected to the load cell and a fixed platform. 600μΙ_ of gel sample was loaded on the surface of the measuring probe (2.5 cm diameter). The tissue biopsy was attached to the fixed platform using cyanoacrylate adhesive. The movable probe was lowered in order to bring the gel in contact with the tissue. A preload of 0.5 N was applied for 60 sees following which the movable probe was raised at a constant speed of 0.1 mm/s and the force required to do so was recorded as a digital signal.

Results and discussion:

Figure 1 shows the results from tensile testing to compare the bioadhesion of the formulation of Example 2 to that of the Universal placebo base. Bioadhesion of both formulations was found to be comparable.

Example 4 - Drug transport kinetics A study was carried out to evaluate the drug transport characteristics of the formulation of Example 2 as a whole and diluted with vaginal fluid stimulant (VFS) using the Static Franz cell system. Materials:

Acetonitrile (Fisher Scientific)

Methanol (Fisher Scientific)

Ammonia Solution (Mallincrodt)

Lecithin (granular) (Spectrum)

DMSO (VWR)

Polyvinylidene-fluoride (PVDF) membrane (Millipore)

Porcine vaginal tissue

Methods:

Preparation of sink media: Tinidazole is a hydrophilic drug with LogP of -0.41 while tioconazole is hydrophobic with a LogP of 4.86. To study the release profile of the formulation it was necessary to produce a suitable sink media that would solubilize both the drugs released from the gel. 1 % lecithin and 5% DMSO in phosphate buffered saline (pH 7.2) was used as a suitable sink medium that solubilized both drugs.

Diluting gel with VFS: The gel to be studied was diluted 10% with VFS in a 20 mL scintillation vial. The contents were mixed well with a spatula and left overnight for uniform mixing. The diluted gel was then used the next day for the release study. Method for transport studies: The transport studies were conducted using a Franz cell system (PermeGear, Riegelsville, PA). The Franz cells were water jacketed and temperature was maintained at 37 ^< Ό throughout the experiment via a circulating water bath. 1 % lecithin and 5% DMSO in phosphate buffered saline (pH 7.2) was used as the receptor medium. Permeability studies were conducted using both PVDF membrane (0.45 μηι) and porcine vaginal tissue (approx. 400 to 700 μηι in thickness). The volume of the receiver chamber was 15 ml of the PVDF study and 5 ml for the tissue study and was continuously stirred by a magnetic stir bar. For release studies using porcine vaginal tissue, 12 mm biopsies were cut and mounted on Franz cells with their epithelial side facing the donor chamber and the connective tissue side facing the receiver chamber. 100 mg of the gel was loaded into each donor chamber. At regular time intervals 400 μΙ of receptor media was removed from the receiver compartment and replaced with fresh media. Results were adjusted for the dilution of the receiver chamber and analyzed by HPLC. At the end of the study the remaining gel was extracted from the donor chamber and analyzed to obtain the mass balance.

Gel extraction from the donor chamber: At the end of the experiment, the donor chamber was rinsed 3 to 4 times with methanol in a clean beaker using a wash bottle (when using the PVDF membrane the membrane was put in the beaker containing methanol for 1 min and taken out while tissues were stored at -eO'C). The solution was transferred to a 10 ml volumetric flask. The flask was sonicated for 5 mins and vortexed for 1 min. The volume was then made up and 1 ml of the solution was filtered and transferred to HPLC for analysis.

Results:

Figures 2a, 2b, 3a and 3b show the comparative drug release (whole and diluted with 10% VFS) from the formulation through PVDF membrane.

Figures 4a, 4b, 5a and 5b show the comparative drug release (whole and diluted with 10% VFS) from the formulation through porcine vaginal tissue.

Conclusions:

Release kinetics through PVDF membrane: The formulation according to the invention shows a burst release for tinidazole and an extended release for tioconazole. The release kinetics profile did not change much with 10% dilution with VFS.

Release kinetics through porcine vaginal tissue: Drug permeability across vaginal tissue depends on the physicochemical properties of the drug therefore tinidazole being hydrophilic in nature permeated quickly through the spaces in the tissue while tioconazole because of its hydrophobic nature permeated solely by the transcellular route. Dilution with VFS did not significantly affect the release pattern.