FIELD OF FIELD
The present disclosure relates to colloidal compositions of griseofulvin for topical use in the treatment of fungal infections of skin and nails. The disclosure also provides the process and methods for preparing such dosage forms.
BACKGROUND AND PRIOR ART
Griseofulvin [(2S,67?)-7-chloro-2\4,6-trirnethoxy-6'-methyl-3//, 47/-spiro[l-benzofuran-2,l'-cyclohex[2]ene]-3,4'-dione)] is a heterocyclic benzofuran extracted from Penicillium griseofulvum. The clinical utility of the drug against mycotic disease of the skin, hair, and nails due to common dermatophytes like Microsporum, Trichophyton, or Epidermophyton was demonstrated around 1960's. Initially the drug was used to supplement attack on dermatophytes. Since none other antifungal agents acting on the microtubule target have been discovered it becomes the choice of drug to treat dermatophytosis. Moreover, it was the first antifungal drug to be approved by FDA. Infections that are readily treatable with this agent include infections of the hair {Tinea capitis) caused by Microsporum canis, Microsporum audouinii, Trichophyton schoenleinii, and Trichophyton verrucosum; "ringworm" of the glabrous skin; Tinea cruris and Tinea corporis caused by M. canis, Trichophyton rubrum, T. verrucosum, and Epidermophyton floccosum; and tinea of the hands (T. rubrum and T. mentagrophytes) and beard (Trichophyton species). Griseofulvin also is highly effective in "athlete's foot" or epidermophytosis involving the skin and nails, the vesicular form of which is most commonly due to T. mentagrophytes and the hyperkeratotic type due to T. rubrum.
Up till now, the mode for the delivery of griseofulvin has been oral. The clinical applications of this molecule are restricted due to its poor aqueous solubility, incomplete and highly variable bioavailability (25%-70%) from gastrointestinal tract and numerous side effects associated with oral therapy. Griseofulvin is about 84% bound to the plasma proteins. It is deposited in keratin precursor cells and is concentrated in the stratum corneum of the skin, in nails and in hair, thus preventing invasion of newly formed cells.
Concentrations of 12-15ug are maintained in the skin during long term administration, while concurrent plasma concentration remains at about l-2ug per ml.
Griseofulvin possesses an elimination half life of 9-24 hrs and is chiefly metabolized by liver mainly to 6-demethylgriseofulvin which is excreted in the urine.
The side effect associated with oral therapy includes headache, which is sometimes severe and usually disappears as therapy is discontinued. The incidence of headache may be as high as 15%. The nervous system manifestations include peripheral neuritis, lethargy and mental confusion, impairment of performance of routine tasks, fatigue, syncope, vertigo, blurred vision, transient macular edema, and augmentation of the effects of alcohol. Among the side effects involving the alimentary tract are nausea, vomiting, diarrhea, heartburn, flatulence, dry mouth, and angular stomatitis. Hepatotoxicity also has been observed. Hematologic effects include leukopenia, neutropenia, punctate basophilia, and monocytosis. Blood studies should be carried out at least once a week during the first month of treatment or longer. Common renal effects include albuminuria and cylindruria without evidence of renal insufficiency. Reactions involving the skin are cold and warm urticaria, photosensitivity, lichen planus, erythema, erythema multiforme-like rashes, and vesicular and morbilliform eruptions. Serum sickness syndromes and severe angioedema develop rarely during treatment with griseofulvin. Estrogen like effects has been observed in children. A moderate but inconsistent increase of fecal protoporphyrins has been noted with chronic use.
The oral griseofulvin therapy is contraindicated in patients with porphyria, hepatocellular failure, systemic lupus erythematosus and pregnancy. The drug interacts and diminishes the effect of coumarin anticoagulants and contraceptives. Also the concomitant use of barbiturates usually depresses griseofulvin activity and may necessitate raising the dosage.
Numerous attempts employing various techniques have been reported in literature to enhance the oral bioavailability of this compound. The absorption of griseofulvin is largely influenced by particle size and dissolution rate. U.S. Patent No. 2,900,304 issued in 1959 is an illustration of griseofulvin uses and compositions for oral or parenteral administration employing micronized drug particles.
Marvel et al., 1964 evaluated the influence of surfactant and particle size on bioavailability of griseofulvin when administered orally. The study indicates that bioavailability of the drug is enhanced when administered in very dilute solutions or aqueous suspensions.
Tachibana and Nakamura (1965) and Mayershohn et al., (1966) suggested the use of PVP for forming dispersions of a drug. These solid dispersions or solid solutions of griseofulvin in PVP showed increasing dissolution rates for the drug with increasing proportions of PVP.
The solid dispersions of griseofulvin using water soluble polymers like poloxamers, macrogols, polyethylene glycol (6000), polysorbates have also been investigated by other researchers. The marketed solid dispersion of griseofulvin Gris-PEG™ (Allergan) ultramicrosize tablets shows good bioavailability (Barrett and Hangian, 1975).
Another study by Junginger (1977) indicated that spray-dried products provide systems with higher energy levels in comparison with those of simple mixtures and coprecipitates, and correspondingly greater dissolution rates. Junginger further discloses that the dissolution rates of the simple mixtures were higher when the PVP is increased.
Cheng et al., 1979 reported the solvates of drugs with organic solvents like benzene and chloroform with higher aqueous solubility as compared to original drug.
The adsorption of griseofulvin on fumed silicon dioxide (Abdallah et al., 1983) and spray dried whey (Kraflow) improve drug availability over the microsize formulations (Wagner et al., 1982).
Effervescent solid dispersion of griseofulvin utilizing different carriers (citric acid, succinic acid, tartaric acid) with various ratios of sodium bicarbonate indicate an increase in dissolution rate as the proportion of sodium bicarbonate increase in carrier system (Desai et al, 1989).
In another study PVP-griseofulvin coprecipitates, griseofulvin-phospholipid coprecipitates, griseofulvin-hydrogenated soya phospholipid coprecipates (Nishihata et al, 1988), griseofulvin-methyl cellulose-PEG coprecipitates (Alden et al, 1993) are investigated. The addition of cholesterol to griseofulvin-phospholipid coprecipitates increased the drug dissolution, reduced the residual chloroform content and decreased the aging towards lower dissolution behavior (Vudhathala and Rogers, 1991). Microencapsulation of griseofulvin-phospholipid coprecipitates indicated controlled release of the drug (Vudhathala and Rogers, 1992).
The bioavailability of micronized (Fulvicin U/F™, Grifulvin V™, Grisactin™) and ultamicronized (Fulvicin P/G™, Grisactin Ultra™) forms was reported to be more as compared to the non-micronized forms (Elamin et al., 1994).
Cyclodextrin complexes with the drug have also been reported to increase the solubility of griseofulvin (Hoshino et al, 1993; Dhanaraju et al, 1998 and Veiga et al, 1998).
Various other attempts have also been reported in the literature to increase the oral bioavailability of griseofulvin e.g. enhanced dissolution by deposition on disintegrants like sodium starch glycolate (Primojel II), carboxymethylcellulose sodium (Nymcel) (Law and Chiang, 1990), molecular association between griseofulvin and chitosan (Sheng et al, 1993), polyethylene glycol (6000), formation of binary and ternary systems (Veiga et al, 1993), by using bioadhesive polymers like polyacrylic acid crosslinked with 2,5-dimethyl-l,5-hexadiene (Tur et al, 1997), cogrinding with water soluble polymers like hydroxypropyl methylcellulose (Sugimoto et al, 1998), novel capsule formulation (using the film forming technique) with 10% ethyl alcohol hydroxypropyl cellulose solution coating (Fell et al, 1998), new dosage forms like multiple emulsions (Onyeji et al, 1991), liposomal suspension (Stozek and Vorysriwicz, 1991) and dry emulsion (Vyas et al, 1992) to increase oral absorption.
Extensive literature survey suggests that griseofulvin is although very effective fungistatic antibiotic its oral route is not favored due to its poor oral bioavailability as a consequence of its low water solubility and numerous unwanted side effects. Further, as usually upper layers of skin are infected, it would be advantageous to employ griseofulvin topically. Due to its strong hydrophobic character and its insolubility in polar solvents it is difficult to deliver this molecule topically in therapeutically effective concentration using conventional topical dosage forms such as solutions, ointments, creams and gels etc.
Literature reports indicate the use of vehicles such as dimethyl acetamide (Arthur and Night, 1974), dimethyl sulphoxide (Post 1979), ointment (Ritschel and Hussain, 1988) nail lacquer (Nimni et al., 1990), gels (Vlachou et al, 1992), spray (Aly et al., 1994), positively and negatively charged submicron emulsions (Piemi et al, 1999), emulsions and suspensions (Fujii et al., 2000) of griseofulvin for effective topical treatment of dermatophytosis. These attempts to provide a non-toxic, effective topical medication of griseofulvin have been unsuccessful because the resultant
solutions were toxic or exhibited other properties which severely limited their effectiveness and applicability. For example, two particular aprotic solvents dimethyl sulfoxide and dimethyl formamide can be used as solvents for griseofulvin which enable griseofulvin to penetrate skin and keratinous tissue. However, both of these solvents are toxic compounds. In fact, dimethyl sulfoxide was generally taken off the market for medicinal use by the U.S. Food and Drug Administration years ago (Farinas, 1996).
U.S. Patent No. 3,899,578, filed in 1974 discloses topical griseofulvin compositions comprising of griseofulvin dissolved in various high boiling, volatile solvents, e.g., propylene carbonate, dimethylphthalate, 3-phenoxypropanol, 4-chlorophenoxyethanol, phenoxyethanol, phenylethanol, eugenol and benzyl alcohol. Benzyl alcohol in combination with dimethyl phthalate, propylene carbonate or eugenol is disclosed as preferred solvent carrier. These compositions will leave an oily residue for a considerable amount of time after application. It is believed that griseofulvin is solubilized in the oily layer of the composition and will rub off on the clothing or upon washing and thus will not be absorbed to any great extent by the skin.
U.S. Patent No. 4039664 filed in 1975 discloses the topical antifungal compositions of griseofulvin using a mixture of 2-pyrrolidone and N-methyl-2-pyrrolidone. Griseofulvin may be dissolved in a vehicle system of this disclosure and topically applied to affected areas of the skin in any convenient dosage form, e.g. cream, ointment, lotion, spray, gel, aerosol, solution.
U.S. Patent No. 4,820,724 filed in 1986 also discloses a griseofulvin composition for topical application to the skin. The solvent carrier system disclosed in this patent is a mixture of a fugitive solvent (viz. n-propanol, isopropyl alcohol, acetone, ethyl alcohol, propylene glycol and butyl alcohol) having a boiling point of less than 110°C and a delivery solvent having a boiling point of greater than 120°C. The delivery systems described in this patent may be effective in promoting the absorption of griseofulvin through the skin; however, these delivery systems are easy to remove accidentally and therefore are not convenient to use. Moreover, after application the fugitive solvent or solvents quickly dissipate by evaporation, due to the body temperature of the patient, leaving as a residue a thin film of the benzyl alcohol-griseofulvin solution on the effected area. Although the investigators claim that even when the fugitive solvent dissipates, griseofulvin becomes highly concentrated in the
benzyl alcohol and remains in solution and does not precipitate out of the benzyl alcohol. At this step if any griseofulvin precipitates out of the benzyl alcohol would not be in a form to be absorbed into the dermis.
U. S. Patent No. 20070098805 filed in 2006 cites the nanoparticle compositions of griseofulvin preferably with an effective average particle size of less than about 2 microns which may be administrated via oral, pulmonary, rectal, opthalmic, colonic, parenteral, intracisternal, intravaginal, intraperitoneal, local, buccal, nasal, and topical routes. The composition may be incorporated into any suitable dosage form like liquid dispersions, oral suspensions, gels, aerosols, ointments, creams, tablets, capsules, sachets, lozenges, powders, pills, and granules and modified for controlled release formulations, fast melt formulations, lyophilized formulations, delayed release formulations, extended release formulations, pulsatile release formulations, and mixed immediate release and controlled release formulations.
Shishu and N. Aggarwal (2006), Preparation of hydrogels of griseofulvin for dermal application, Int. J. Pharm., 326:20-24, focus on the hydrogel formulations of griseofulvin comprising of Carbopol 934P as base, essential oils, propylene glycol, N-methyl-2-pyrrolidone as penetration enhancers for topical delivery of the drug.
All of the above cited prior arts discloses or envisages micronized and ultramicronized tablets, solid dispersions, solvates, coprecipitates, complexes of griseofulvin with suitable polymers/carrier systems for improvement in bioavailability through oral route. There is no topical formulation available in the market which could safely deliver the drug topically and result in sufficient retention of griseofulvin in the skin to be useful therapeutically.
Topical delivery of drugs by colloidal systems has evoked a considerable interest because of several advantages
> act as drug carriers to deliver entrapped drug molecules into or across the skin;
> act as penetration enhancers owing the penetration of the individual lipid components into the stratum corneum and subsequently the alteration of the intercellular lipid lamellae within this skin layer;
> serve as a depot for sustained release of dermally active compounds;
> serve as a rate-limiting membrane barrier for the modulation of systemic absorption, hence providing a controlled transdermal delivery system.
For topical delivery of griseofulvin prior arts disclose use of aprotic solvents, fugitive solvents for formulating ointments, gels, emulsions, sprays and nanoparticulate systems. However, none of these has been found to result in continuous presence of therapeutic amounts of griseofulvin in the epidermis, especially the stratum corneum layer of skin. Despite several investigations and numerous observations regarding the effectiveness of topically applied griseofulvin, this route of administration remains within the area of experimental therapeutics. Thus, there is a need to improvise the solubility as well as the penetrability of the drug simultaneously so as to ensure therapeutic dermal targeting. In lieu of the above mentioned reports and facts novel colloidal carrier systems like microemulsions, liposomes and ethosomes (containing optimized quantities of various surfactants, cosurfactants and penetration enhancers) were developed and investigated to deliver the drug dermally efficiently and effectively. The formulation results in better patient compliance and more reliable therapeutic results and also reduction in the dose of the drug as griseofulvin will be directly delivered to the affected areas.
SUMMARY
The present disclosure relates to a colloidal compositions of griseofulvin comprising 0.1% to 1.0% w/w of griseofulvin, 1.0% to 30.0% w/w of a lipid or its derivative, 15.0% to 50.0% w/w of a surfactant, 1.0% to 20.0% w/w of a co-surfactant, 0.5% to 25% w/w of at least one penetration enhancer and 25% to 80% w/w of water.
The disclosure further relates to a colloidal composition of griesofulvin comprising 0.1% to 1.0% w/w of griseofulvin, 0.5% to 10.0% w/w of at least one phospholipids, 0.1%-1% w/w of at least one sterol and 98.0- 99.0% w/w water.
The disclosure further relates to a colloidal composition of griseofulvin comprising 0.1% to 1.0% w/w of griseofulvin, 0.5% to 10.0% w/w of at least one phospholipid, 0.5% to 25% w/w of at least one penetration enhancer, 25% to 80% w/w of water and 10% to 50% w/w of at least an alcohol.
Further, the disclosure relates to the process for the preparation of the colloidal compositions of griseofulvin.
The colloidal composition of griseofulvin of the present disclosure is designed to deliver the drug dermally in effective amounts, increase bioavailability and circumvent the side effects associated with the conventional oral therapy with localized drug delivery.
The disclosure is based on the fact that topically applied griseofulvin is carried into the stratum corneum using these drug carriers and is retained well in the upper layers of skin in therapeutically effective amounts and thereby successfully treats fungal skin problems caused by common dermatophytes. Moreover, once griseofulvin penetrates the stratum corneum, it is retained there and resists being removed by washing for substantial time periods.
These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This Summary is provided to introduce a selection of concepts in a simplified form. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The features, objects and advantages will be evident from the following description of the preferred embodiments of the present disclosure taken in conjunction with the accompanying drawing in which;
Fig. 1: Transmission electron micrograph of microemulsion (M-IV) at 120000 X magnification;
Fig. 2: Transmission electron micrograph of griseofulvin ethosomes at 50000 X
magnification; Fig. 3a: Comparison of mean cumulative amount of griseofulvin permeated/area
(|o.g/cm2) from formulations E I (control) and ME I through mice skin after 24 h; Fig. 3b: Comparison of flux value (ug/cm /h) of griseofulvin from formulations E I
(control) and ME I through mice skin; Fig. 4a: Comparison of mean cumulative amount of griseofulvin permeated/area
(ug/cm2) from formulations E II (control) and ME II through mice skin after 24
h; Fig. 4b: Comparison of flux value (jag/cm2/h) of griseofulvin from formulations E II
(control) and ME II through mice skin; Fig. 5a: Comparison of mean cumulative amount of griseofulvin permeated/area
(ug/cm2) from formulations ME II, ME III, ME IV, ME V and ME VI through
mice skin after 24 h;
Fig. 5b: Comparison of flux value (ug/cm /h) of griseofulvin from formulations ME II,
ME III, ME IV, ME V and ME VI through mice skin; Fig. 5c: Comparison of skin retention (ug/cm ) of griseofulvin from formulations ME
II, ME III, ME IV, ME V and ME VI after 24 h; Fig. 6a: Comparison of mean cumulative amount of griseofulvin permeated/area
(|ig/cm ) from formulations ME IV (without enhancer), ME VII, ME VIII, ME
IX and ME X through mice skin after 24 h; Fig. 6b: Comparison of flux value (ug/cm2/h) of griseofulvin from formulations ME IV
(without enhancer), ME VII, ME VIII, ME IX and ME X through mice skin; Fig. 6c: Comparison of skin retention (ug/cm ) of griseofulvin from formulations ME
IV (without enhancer), ME VII, ME VIII, ME IX and ME X after 24 h; Fig. 7a: Comparison of mean cumulative amount of griseofulvin permeated/area
(ug/cm2) from liposomes (control), ET I, ET II and ET III through mice skin
after 24 h; Fig. 7b: Comparison of flux value (ug/cm /h) of griseofulvin from liposomes (control),
ET I, ET II and ET III through mice skin Fig. 7c: Comparison of skin retention (|u,g/cm2) of griseofulvin from liposomes
(control), ET I, ET II and ET III after 24 h; Fig. 8a: Comparison of mean cumulative amount of griseofulvin permeated/area
(l^g/cm2) from liposomal gel (control), ET Gel I, ET Gel II and ET Gel III
through mice skin after 24 h; Fig. 8b: Comparison of flux value (|ag/cm2/h) of griseofulvin from liposomal gel
(control), ET Gel I, ET Gel II and ET Gel III through mice skin; Fig. 8c: Comparison of skin retention (p.g/cm ) of griseofulvin from liposomal gel, ET
Gel I, ET Gel II and ET Gel III after 24 h; and Fig. 9a: Hematoxylin-eosin stained section of mouse skin with no treatment (Control). Fig. 9b: Hematoxylin-eosin stained section of mouse skin treated with griseofulvin
microemulsion ME IV Fig. 9c: Hematoxylin-eosin stained section of mouse skin treated with griseofulvin
microemulsion ME VII Fig. 9d: Hematoxylin-eosin stained section of mouse skin treated with griseofulvin
microemulsion ME VIII
Fig. 9e: Hematoxylin-eosin stained section of mouse skin treated with griseofulvin ethosomal gel ET Gel III.
DETAILED DESCRIPTION
The present disclosure relates to colloidal carrier based dermal drug delivery systems of griseofulvin that is useful for the treatment of fungal skin infections caused by dermatophytes. These compositions provide localized therapy and enhanced bioavailability.
In an embodiment of the present disclosure the colloidal composition of griseofulvin comprise 0.1% to 1.0% w/w of griseofulvin, 0.5% to 30.0% w/w of a lipid or its derivative and 25% to 99% w/w of water.
In an embodiment of the present disclosure the colloidal composition of griseofulvin comprises 0.1% to 1.0% w/w of griseofulvin, 1.0% to 30.0% w/w of a lipid or its derivative, 15.0% to 50.0% w/w of a surfactant, 1.0% to 20.0% w/w of a co-surfactant, 0.5% to 25% w/w of at least one penetration enhancer and 25% to 80% w/w of water. The colloidal composition is in the form of a microemulsion.
The lipid or its derivative used in the colloidal composition of the disclosure is selected from a group consisting of diesters of caprylic/capric acid, isopropyl myristate, isopropyl isostearate, isopropyl linoleate, isopropyl palmitate, medium chain triglycerides, oleic acid, palmitic acid, lauric acid, linoelaidic acid, linoleic acid, linolenic acid, glycolyzed ethoxylated glycerides of natural oils, lauric acid hexyl esters, or a mixture thereof.
In an embodiment of the disclosure the lipid or its derivative is either medium chain triglyceride of caprylic/capric acid or isopropyl myristate.
The surfactant used in the colloidal composition of the disclosure is selected from a group consisting of polyglycolyzed glyceride, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene glycol ether, decaethylene glycol monododecyl ether, diethylene glycol monodecyl ether, ethylene glycol monoalkylalkyl ether, sorbitan ester, isopropyl alcohol, diethylene glycol monoethyl ether, phosphatidylcholine derivatives, lecithins, propylene glycol, polyethylene glycol, polyethylene oxide, polysorbate, polyglyeryl oleate, propylene glycol laurate, polyglycerol fatty acid ester, poloxamer, macrogol, or a mixture thereof.
The co-surfactant used is selected from a group consisting of polyoxyethylene alcohol ester, isopropanol, sorbitan monooleate, glycerol, benzyl alcohol, 1-propanol, 1-butanol, 1-hexanol, 1-octanol, 1,2-alkanediols, 1,2-propanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, propylene glycol, polyethylene glycol, oleic esters of polyglycerol, ethyldiglycol, or mixture thereof.
In another embodiment of the present disclosure a colloidal composition of griesofulvin comprises 0.1% to 1.0% w/w of griseofulvin, 0.5% to 10.0% w/w of at least one phospholipid 0.1%-1% w/w of at least one sterol and 98.0- 99.0% w/w water. This composition is in the form of a liposome.
In yet another embodiment of the present disclosure a colloidal composition of griseofulvin comprises 0.1% to 1.0% w/w of griseofulvin, 0.5% to 10.0% w/w of at least one phospholipid, 0.5% to 25% w/w of at least one penetration enhancer, 25% to 80% w/w of water and 10% to 50% w/w of at least an alcohol. The colloidal composition is in the form of an ethosome.
The phospholipid used in the present disclosure is selected from the group consisting of phosphatidyl choline, hydrogenated phosphatidyl choline, phosphatidic acid, soya phosphatidyl choline, egg phosphatidyl choline, dipalmityl phosphatidyl choline, distearyl phosphatidyl choline, phosphatidyl serine, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol, or mixtures thereof.
The sterol used in the colloidal composition of the disclosure is selected from the group consisting of cholesterol, cholesterol oleate, cholesterol acetate, cholesterol palmitate, campesterol, p-sitosterol, l,2-dimyristoyl-snlycero-3-phosphatidylcholine (DMPC), or a mixture thereof.
In another embodiment, the penetration enhancer is selected from a group consisting of N-methyl-2-pyrrolidone, hexyl-4-methyloxycarbonyl-2-pyrrolidone, 1-hexyl-2-pyrrolidone, 1 -(2-hydroxyethyl)-pyrrolidone, 1 -lauryl-4-methyloxycarbonyl-2-pyrrolidone, poly (N-vinylpyrrolidone), menthol, peppermint oil, eucalyptus oil, cardamom oil, 1-carvone, cineole, eucalyptol, eugenol, nerolidol, Vitamin E (a-tocopherol), propylene glycol, phosphatidylcholine, lecithins, diethyl glycol monoethyl ether, alcohol, polyol, esters, surface active agents and phospholipids, or combination thereof.
The alcohol used is either ethanol or isopropyl alcohol or a mixture thereof.
In another embodiment of the disclosure the composition is a topical formulation. The topical formulation is preferably in form of a gel.
In an another embodiment of the present disclosure a process for preparing the colloidal composition of griseofulvin comprises providing a mixture of griseofulvin in the range of 0.1 % to 1.0 % w/w of the composition with oil phase ingredient in the range of 1.0 % to 30.0 % w/w of the composition, a surfactant in the range of 15.0 % to 50.0 % w/w of the composition, a co-surfactant in the range of 1.0 % to 20.0 % w/w of the composition, a penetration enhancer in the range of 0.5 % to 20.0 % w/w and aqueous phase in the range of 25.0 % to 80.0 % w/w of the composition.
In another embodiment of the present disclosure a process for preparing the colloidal composition of griseofulvin comprises providing a mixture of griseofulvin in the range of 0.1 % to 1.0 %w/w of the composition with a phospholipid in the range of 0.5 % to 10.0 % w/w of the composition, a sterol in the range of 0.1 % to 1.0 % w/w of the composition and aqueous phase in the range of 98.0 % to 99.0 % w/w of the composition.
In yet another embodiment of the present disclosure a process for preparing the colloidal composition of griseofulvin comprises providing a mixture of griseofulvin in the range of 0.1 % to 1.0 % w/w of the composition with a phospholipid in the range of 0.5 % to 10.0 % w/w of the composition, an alcohol in the range of 10.0 % to 50.0 % w/w of the composition, a penetration enhancer in the range of 0.5 % to 25.0 % w/w and aqueous phase in the range of 25.0 % to 80.0 % w/w of the composition.
Another embodiment of the present disclosure is colloidal carrier based dermal drug delivery systems which offer localized/targeted and enhanced drug delivery to epidermis and stratum corneum with pharmacodynamic and pharmacokinetic advantages.
In another embodiment of the composition of the present disclosure is that the dermal delivery system is preferably formulated as colloidal carrier based systems such that the compound under consideration i.e., griseofulvin is solubilized completely in the carrier system which also enhances partitioning of the drug in the epidermis/stratum corneum, so as to deliver griseofulvin substantially at the desired site of absorption, i.e., preferably the upper layers of epidermis.
Further another embodiment of the present disclosure is that the ingredients reducing interfacial tension which allow emulsification and easier spreading of the
formulation include surfactants selected from the group consisting of polyglycolyzed glycerides, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene glycol ethers, decaethylene glycol monododecyl ethers, diethylene glycol monodecyl ethers, ethylene glycol monoalkylalkyl ethers, sorbitan esters, isopropyl alcohol, diethylene glycol monoethyl ether , phosphatidylcholine derivatives (lecithins), propylene glycol (diol alchol), polyethylene glycol (polyethylene oxide or polyoxyethylene), alcohols (isopropyl alcohol), polysorbates, polyglyeryl oleate, propylene glycol laurate, polyglycerol fatty acid esters, Poloxamers, Macrogols, or a mixture thereof and co-surfactants selected from the group consisting of polyoxyethylene alcohol ester, isopropanol, sorbitan monooleate, glycerol, benzyl alcohol, short chain alcohols (1-propanol, 1-butanol, 1-hexanol, 1-octanol), 1,2-alkanediols (1,2-propanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol), propylene glycol, polyethylene glycol, oleic esters of polyglycerol, ethyldiglycol, derivatives or mixture thereof but not limited to it.
Yet another embodiment of the present disclosure is that the proportions of surfactants and co-surfactants are optimized to obtain a favorable hydrophilic lipophilic balance such that not only the drug dissolves completely in the system but also partitions from the system when it comes in contact with the skin.
Another embodiment of the present disclosure is that surfactants and the co-surfactants comprise materials, which are non-toxic and pharmaceutically acceptable. These may be natural, semi-synthetic, synthetic or man-modified.
Further another embodiment of the present disclosure is that the penetration enhancers increase percutaneous absorption of compounds by increasing diffusivity of the stratum corneum and/or by disrupting the intercellular lipid barrier. More precisely the terpene derivatives enhance the electrical conductivity of the tissues thereby opening the polar pathways within the stratum corneum.
Another embodiment of the present disclosure is that the composition is in the form of colloidal carrier systems for topical delivery (transparent microemulsions or deformable liposomal formulations i.e., ethosomes), but not limited to it.
Another embodiment of the pharmaceutical composition of the present disclosure is that the colloidal carrier compositions help in partitioning and retention of the compound in the upper layers of skin.
Further, another embodiment of the present disclosure is that griseofulvin is formulated into colloidal dermal drug delivery systems. This localized dermal application of griseofulvin may not only reduce the body burden associated with oral therapy, but also help targeting the dermis with enhanced penetrability and retention in the skin. This therapeutic efficacy is contemplated to reduce the dose without unnecessary saturation of the whole system with toxic drug and enhance patient compliance.
The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure.
EXAMPLES
The examples given are merely illustrative of the uses, processes and products claimed in this disclosure, and the practice of the disclosure itself is not restricted to or by the examples described.
Example 1:
Preparation of griseofulvin emulsion E I

Table Remove
The emulsion E I composition of griseofulvin was prepared by dissolving the drug in oil phase i.e., isopropyl myristate, followed by addition of Tween 40. This mixture was triturated in a mortar and pestle with the addition of TDW. This conventional emulsion formulation was used as one of the control. Example 2: Preparation of griseofulvin emulsion E II
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The emulsion E II composition of griseofulvin was prepared by dissolving the drug in oil phase i.e., Captex 200, followed by addition of Tween 80. This mixture was triturated in a mortar and pestle with the addition of TDW. This conventional emulsion formulation was used as one of the control. Example 3: Preparation of solid dispersion of griseofulvin with PEG 4000
A solid dispersion of griseofulvin with PEG 4000 at a 1:10 drug: polymer ratio was prepared by melting a weighed quantity of PEG 4000 (1000 mg) in a beaker maintained at 64-69°C. The weighed quantity of griseofulvin (100 mg) was thoroughly mixed with the molten polymer. The drug-polymer molten mixture was then cooled rapidly in ice. The hardened dispersion was powdered in a mortar, passed through B.S.S sieve #100 and stored in a dessicator. Example 4: Preparation of microemulsion of griseofulvin ME I

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Griseofulvin-PEG 4000 solid dispersion (as prepared in Example 3) was added to the mixture of isopropyl myristate, Tween 80 and isobutanol in a beaker which was magnetically stirred for approximately 1 h until the drug dissolved completely in the mixture. This mixture was then diluted with TDW dropwise with continuous stirring. After each addition, the sample was allowed to mix thoroughly and checked for clarity/transparency.
xample 5: Preparation of griseofulvin microemulsion ME II

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Microemulsion of griseofulvin was prepared by adding the drug to the mixture of Captex 200, Tween 80 and co-surfactant (Phospholipon 90G) in a beaker magnetically stirred at 60°C. Then an appropriate amount of TDW was added to the mixture drop by drop and clear microemulsion containing griseofulvin was obtained by stirring the mixture for another 10 min. Example 6: Preparation of griseofulvin microemulsion ME III

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The microemulsion was prepared using the procedure mentioned in Example 5 using ingredients mentioned above.
Example 7:
Preparation of griseofulvin microemulsion ME IV

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The microemulsion was prepared using the procedure mentioned in Example 5 using ingredients mentioned above.
Example 8:
Preparation of griseofulvin microemulsion ME V

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The microemulsion was prepared using the procedure mentioned in Example 5 using ingredients mentioned above.
Example 9:
Preparation of griseofulvin microemulsion ME VI

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The microemulsion was prepared using the procedure mentioned in Example 5 using ingredients mentioned above. Example 10: Preparation of griseofulvin microemulsion ME VII

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""Indicates optimized concentration of N-methyl-2-Pyrrolidone
Microemulsion of griseofulvin was prepared by adding the drug to the mixture of Captex 200, Tween 80, Transcutol P and N-methyl-2-pyrrolidone (as a penetration enhancer selected from the class of pyrrolidone derivatives) in a beaker magnetically stirred at 60°C. Then an appropriate amount of TDW was added to the mixture drop by drop and clear microemulsion containing griseofulvin was obtained by stirring the mixture for another 10 min. Example 11: Preparation of griseofulvin microemulsion ME VIII

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Indicates optimized concentration of Menthol
The microemulsion was prepared using the procedure mentioned in Example 10 using ingredients mentioned above. Example 12: Preparation of griseofulvin microemulsion ME IX

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The microemulsion was prepared using the procedure mentioned in Example 10 using ingredients mentioned above.
Example 13:
Preparation of griseofulvin microemulsion ME X

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The microemulsion was prepared using the procedure mentioned in Example 10 using ingredients mentioned above. Example 14: Preparation of griseofulvin liposomal suspension

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Liposomal suspension was prepared by the conventional rotary evaporation sonication method. Phospholipon 90G, cholesterol and griseofulvin were dissolved in chloroform in a dry round bottom flask. The organic solvent was removed by rotary evaporation and the film formed was hydrated with TDW. This preparation was used as controls for comparison with the ethosomal compositions.
Example 15:
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Preparation of griseofulvin liposomal gel

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Griseofulvin liposomes were gelled by replacing for the Carbopol gel. Carbopol 940 was soaked overnight in 4.0 g water and neutralized with triethanolamine (1-2 drops). This was then mixed with pre-prepared liposomal suspension and stirred continuously at 500-1000 rpm with the help of a mechanical stirrer to get the gel.
Example 16:
Preparation of griseofulvin ethosomal composition ET I

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Elastic ethosomes were prepared by cold method. Griseofulvin, phospholipon 90G and penetration enhancer(s) were dissolved in ethanol at 30°C in 25ml beaker. TDW maintained at 30°C was added in aliquots (1 ml) while stirring the ethanol solution with the help of a mechanical stirrer at 2000-3000 rpm. After all the TDW was added, the contents are allowed to stir for additional 5 min. The prepared formulations were stored at refrigerated (8-15 °C) conditions. Example 17:
Preparation of griseofulvin ethosomal composition ET II

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The ethosomal composition was prepared using the procedure mentioned in Example 16 using ingredients mentioned above. Example 18: Preparation of griseofulvin ethosomal composition ET III
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The ethosomal composition was prepared using the procedure mentioned in
Example 16 using ingredients mentioned above. Example 19:
Preparation of griseofulvin ethosomal gel composition ET Gel I, II and III
The ethosomal compositions I, II and III were gelled as mentioned in example 15 to obtain ethosomal gel compositions ET Gel I, II and III respectively. Example 20: Physical characterization of various griseofulvin microemulsions
The griseofulvin microemulsions were evaluated for the drug content, pH, rheology, globule size and size distribution, polydispersity index, zeta potential, surface morphology and stability.
It was observed that drug content was in the range of 97.57±0.77% to 99.54±0.94% for all the microemulsion formulations ensuring uniform distribution of the drug throughout the formulations.
The pH values of different microemulsion and formulations of griseofulvin was found to be between 6.40 - 6.78, matching the range of slightly acidic pH of the human skin. The microemulsions exhibited a Newtonian flow behavior and their viscosity was found to be in the range of 105.3 - 289.7 mPa.s at 29°C; indicated the suitability of these formulations for topical applications.
The mean globule size of the microemulsions ranged from 18.1 - 31.1 nm with ME II possessing larger globule size which may be attributed to presence of phospholipon (lecithin) in the formulation. The polydispersity index ranged from 0.298 - 0.953 and the zeta potential varied from -9.57 to -22.2 mV. All the microemulsion formulations appear to be stable as zeta potential falls between -10 to -30 mV (closer to +/-30 mV of the isoelectric point (0 mV) in aqueous solutions).
The transmission electron microscopic pictures (Fig.l) of microemulsions revealed that the microemulsified droplets were spherical in shape, surrounded with a coat of surfactant which provides it stability and uniformly dispersed all over in continuous phase. Example 21: Stability studies of various griseofulvin microemulsions
The microemulsion formulations were studied for stability at 4°, 25° and 40° C for 5 months and periodically evaluated for transparency, pH, drug content, feel and viscosity. The results revealed that in formulations stored at 4°C there was negligible change in % drug content but turbidity occurred in the after the second month which disappeared when the formulations were brought at room temperature. Although the microemulsions remained clear even after a period of 5 months at temperature 25 and 40°C, but there was a small decline (2-3%) in the % drug content at 25°C and 40°C. All the microemulsion formulations were found to be consistent with respect to their pH values, transparency, during this period.
Example 22:
Physical characterization of various griseofulvin ethosomes and ethosomal gel
compositions
The vesicular compositions were evaluated for the drug content, pH, rheology, entrapment efficiency, vesicular size and size distribution, polydispersity index, zeta potential, surface morphology and membrane elasticity.
The drug content was in the range of 96.12±0.86% to 99.65±0.59% for all the ethosomes and ethosomal gel formulations ensuring uniform distribution of the drug throughout the formulation(s).
The pH values of different ethosomal formulations of griseofulvin were found to be between 6.4-6.8, matching the range of slightly acidic pH of the human skin.
The ethosomal compositions possessed very low viscosity; however, the ethosomal gels possessed viscosity in the range of 66466.07 - 32351.92 mPa.s at 29°C.
The drug entrapment efficiency increased with increase in the amount of phospholipon (lecithin) (65.20 ±0.13 % to 73.26 ± 0.34 %) used in the preparation and no significant difference (P<0.05) in the entrapment efficiency was observed even after sonication (65.30 ± 0.12 % to 72.36 ± 0.14 %); which may be due unchanged integrity of vesicular systems attributed to elasticity of this particular vesicular system.
The mean vesicular size of ethosomes containing propylene glycol and Transcutol P was observed to be 402 and 703nm respectively indicating that on incorporating Transcutol P as penetration enhancer, particle size shifts to the higher side. However, polydispersity index for both the formulations was found to be nearly 0.15. Zeta potential for ethosomal formulations was observed to be in the range -25mV to -36mV (zeta potential of nearly -30 mV indicates good physical stability) indicating good stability of these systems with respect to surface charge.
The morphological studies showed that although ethosomes appeared as round vesicles, but these were not perfectly round due to their malleable character (Fig. 2).
The flux of liposomal and ethosomal compositions through a microporous filter membrane and further evaluation by dynamic light scattering technique were performed to evaluate the elasticity of vesicles. The vesicle size of ethosomes before and after extrusion was 651 and 483 nm respectively, whereas those of liposomes were 678 and 171nm respectively. This shows that ethosomes were more flexible and ultradeformable as compared to the rigid liposomes which may be attributed to presence of ethanol in the ethosomes. This physical property of the ethosomal compositions would help in easy penetration of the vesicles through the minute pores present in the skin. Example 23:
Methodology for in vitro skin permeation and skin retention studies of vesicular and non-vesicular griseofulvin formulations
In vitro permeation studies of various microemulsion formulations were carried out using fabricated Franz diffusion cell with a diffusional surface area of 5.73 ± 0.28 cm and a volume 31.33 ± 2.08 ml. The receptor compartment was equipped with a magnetic stirring bar and the temperature was kept at 37°C by circulating water through a jacket surrounding the cell body throughout the experiment. Skin of male laca mice were used for all these studies. The hairs of the dorsal skin of mice were removed with the help of a scalpel by bringing it as close as possible to the skin without damaging it. Skin was carefully separated from the fat tissue and blood vessels and rinsed with phosphate buffer. The mice skin was mounted on the receptor compartment with the stratum corneum side facing upward to the donor compartment. The receptor chamber was filled with phosphate buffer saline pH 6.4. Test formulations (equivalent to 1 mg of drug) were applied on to the skin surface. 1 ml sample from the receptor was removed
at appropriate intervals and immediately replaced with fresh receptor solution. Samples were diluted (three times) with the respective solutions and analyzed spectrophotometncally at 296nm. The cumulative amount released per unit area of skin, flux and permeability coefficient of griseofulvin in the receptor compartment were

calculated in (o,g/cm2 ug/hr/cm2and hr/cm2espectively.
At the end of the permeation experiments (24 h), the skin surface was rinsed with methanol to remove excess drug from the surface. The receptor media was then replaced with 50% ethanol. Receptor contents were allowed to stir for next 24 hrs. After 24 hrs, the media was analyzed for amount of drug retained in the skin. During this stage ethanolic receptor media will diffuse into the skin disrupting the cell of skin and vesicular structure of any ethosomes that may have penetrated and deposited in the tissue, and, thus, releasing both ethosomes bound and free griseofulvin for collection by the receptor fluid. Example 24: In vitro skin permeation and skin retention studies of griseofulvin microemulsions
In vitro permeation profile of griseofulvin from microemulsion ME I containing isopropyl myristate as an oil phase indicate 120.45±5.57 ug/cm as mean cumulative drug permeated after 24 h where as only 76.33±2.64 ug/cm2 was released from conventional emulsion EI in 24 h (Fig. 3a). Also the rate of permeation/flux of griseofulvin from ME I was observed to be 13.7 ug/cm /h which was about three times more than E I (Fig. 3b).
Similarly in vitro permeation profile of griseofulvin from microemulsion ME II containing Captex as an oil phase, Tween 80 as surfactant and phospholipon as cosurfactant indicate 151.62±3.21 ug/cm as mean cumulative drug permeated after 24 h where as only 106.42 ± 2.4ug/cm2 ug/cm2 was released from conventional emulsion E II in 24 h (Fig. 4a). Also the rate of permeation/flux of griseofulvin from ME II was observed to be 9.45|ag/cm2/h that was again about three times higher than the value obtained with E II (Fig 4b).
The significant difference in the percutaneous permeation of griseofulvin between microemulsions and emulsion may be attributed to several factors. Microemulsions act as drug reservoirs where drug is released from the inner phase to the outer phase and then further onto the skin. Referable to the small droplet size, droplets settled down to
close contact with the skin and a large amount of inner oil in microemulsions might penetrate into skin.
Microemulsions containing different co-surfactants ME III (Transcutol), ME IV (propylene glycol), ME V (PEG 300) and ME VI (PEG 400) were developed and evaluated for in vitro characteristics. The cumulative amount of drug permeated after 24 h from the above mentioned microemulsions was detected to vary between 123.54±1.91 to 152.24±2.47 |ug/cm2 (Fig. 5a) and the flux value for all these microemulsions ranged from 9.27±0.2 to 9.9±0.05 ug/cm /h (Fig. 5b).
However, the skin retention coefficient for ME IV (propylene glycol) and ME V (PEG 300) was 29.59±1.84 ug/cm2 and 27.01±1.28 ug/cm2 respectively which was two times as compared to ME II (Fig. 5c). This behavior is ascribed to increased solublization of drug in the skin due to presence of these co-surfactants. This increased penetration of the drug from ME IV may be attributed to propylene glycol (co-surfactant). Penetration enhancing property of propylene glycol is thought to result from solvation of a-keratin within the stratum corneum and occupation of proteinaceous hydrogen bonding sites reducing drug-tissue binding and thus promoting permeation.
Further to enhance the skin permeation rate of griseofulvin from the microemulsions, various chemical enhancers {N-methyl-2-pyrrolidone (NMP), menthol, eucalyptus oil and peppermint oil} were included in the optimized microemulsion formulation i.e., ME IV.
The influence of NMP at various concentrations (1.0-10.0% w/w) on skin permeation of griseofulvin was investigated. The most pronounced permeation enhancing effect was shown by ME VII containing 5.0% w/w NMP which possessed 162.2±4.39 ug/cm cumulative drug permeation after 24 h with flux value of 17.03±0.65 ug/cm /h (Fig. 6a, 6b). Although the flux value enhanced nearly 1.5 times as compared to ME IV but the skin retention was found to be 3.05µg/cm2 which was one tenth of that of ME IV (29.59±1.84 ug/cm2). This increased permeation through the skin can be devoted to the interaction of NMP with keratin and lipids of the skin.
Likewise, the influence of menthol at various concentrations (1.0-5.0% w/w) on skin permeation of griseofulvin was also investigated. The flux and permeation coefficient data revealed that, 3.0 % menthol increased the permeation of griseofulvin by 2.4 fold as compared to ME IV (Fig. 6a, 6b). Menthol acts by reducing the order of

intercellular lipid domains. The enhancement in the flux of griseofulvin by menthol could be due to lipid extraction, barrier perturbation, and improvement in the partitioning of the drug to the skin.
It was also concluded that menthol (3.0%w/w) acted as a better penetration enhancer than NMP (5.0%w/w) at a lower concentration (Fig. 6a, 6b).
Eucalyptus oil (ME IX) and peppermint oil (ME X) were also investigated for their penetration enhancing properties. The permeation profiles of ME XI and ME X showing 153.11± 1.12 and 155.73=1=1.59 fig/cm cumulative amount permeation were almost superimposable with that of ME IV (Fig. 6a). Although the values of flux for ME IX and ME X were 11.54±0.11 and 9.63±0.14 ug/cm /h respectively which was similar to ME IV (Fig. 6b) however ME IX and ME X exhibited a significant decline of 3.7 and 3 times respectively in skin retention as compared to ME IV (Fig. 6c). Example 25:
In vitro skin permeation and skin retention studies of liposomal suspension and ethosomal compositions of griseofulvin
The in vitro studies exhibited that all the three ethosomal compositions have almost similar permeation profiles with the cumulative amount released in 24 h ranging from 110.06=1=1.89 to 121.69±0.36 ug/cm. However, this value was greater as compared to mean cumulative amount permeated/area for liposomal suspension after 24 h (89.97±2.47ug/cm2). Also permeation/flux rates were 1.7 times greater than liposomal suspension. This improved permeation profile for the ethosomal formulations against liposomes may be attributed to ethanol present in ethosomal compositions which imparts elasticity to these vesicles as compared to cholesterol in liposomes which provides stability to the liposomal membrane thereby profoundly affecting the membrane properties (Fig. 7a, 7b). The skin retention for ethosomes ranged from 47.56±6.46 to 49.2fttl.69 ug/cmz which was three times higher in contrast to liposomal suspension (Fig. 7c). This effect is ascribed to the deformability of ethosomes as a result of which they get entrapped in the skin and release the drug at a comparative lesser rate for longer time making them more suitable for dermal delivery of drugs.
The action of ethosomes as penetration enhancer may predominantly be on the intercellular lipid of stratum corneum, raising the fluidity and weakness of stratum corneum. Ultradeformable character of ethosomes and presence of unsaturated fatty acids phospholipon (lecithin) in the formulation not only enhances the penetration but
also supports the passage of ethosomes through very fine pores in the skin under
suitable osmotic gradient.
Example 26:
In vitro skin permeation and skin retention studies of griseofulvin liposomal and
ethosomal gel compositions
The ethosomal compositions were gelled to provide the system an optimum viscosity making it suitable for topical applications. The in vitro permeation/flux rates of liposomal and ethosomal gels presented a generalized decline in permeation characteristics (Fig. 8a, 8b). Although all the formulations were affected the decrease in permeation parameters was considerable for ET Gel I which may be ascribed to the type(s) or combination(s) of penetration enhancer(s) in this formulation.
Also, the skin retention studies indicated a reduction in drug retained for the all the ethosomal gel formulations when compared with their respective ethosomal compositions which is possible consequence of decreased diffusion of drug from the gel base (Fig. 8c). Example 27: In vitro comparison of microemulsions and ethosomes
In vitro permeation studies of griseofulvin from microemulsions and ethosomes as drug carriers revealed that both the systems were able to enhance the permeation of drug. Although with ethosomes and microemulsions there was about 2-3 fold enhancement in the flux rate the ethosomal formulations were found to be more effective in retaining the drug in the skin; These studies indicate that these systems had a penetration enhancing effect and also help in the dermal targeting of the drug as it gets entrapped into the skin. The drug was partitioned into the skin to a level which exceeded the MIC of griseofulvin. Example 28:
Histopathological studies of griseofulvin microemulsions and ethosomal gel compositions
Laca mice weighing around 20-25 g were used for the study. The hair on the dorsal side of animals was removed with shaving razor in the direction of tail to head without damaging the skin. One mouse was kept as control (untreated). The selected test microemulsions (ME IV, ME VII and ME VIII), ethosomal gel (ET Gel III) were applied uniformly on the dorsal region. The formulations were kept in contact with skin
for 4 h. After that the animals were sacrificed with overdose inhalation of diethyl ether, the exposed dorsal area was cut. Each specimen was fixed in 10% buffered formalin; embedded in paraffin and microtoned. The sections were stained with hematoxylin and eosin. Finally, the specimens were observed under a high power light microscope and were evaluated for their integrity and tested for stratum corneum, epidermis and dermis thickness. Results were compared with the skin section of untreated mice.
The histologically stained skin samples were checked for their integrity (Fig. 9a - Fig. 9e). The thickness of various skin layers was observed and it was observed that there was no significant difference between skin biopsies taken from various treatments and control. Example 29:
Microbiological studies of griseofulvin microemulsions, ethosomal compositions and ethosomal gel formulations
The microbiological studies were conducted using Microsporum gypseum (MTCC ACC no. 2830) as the test strain (106 colony forming units/ml fungal suspension), using potato dextrose agar (PDA) as the nutrient media. PDA for the agar plates was prepared by dissolving PDA (4% w/w) in water, autoclaved, cooled to 45-50° C, poured into sterile petriplates, allowed to solidify at room temperature for a maximum of 30 minutes, holes of 9 mm in diameter were made with sterile stainless steel borer and filled with formulations (microemulsions and ethosomes) to be tested (equivalent to 75 ug of griseofulvin). The plates were held for 1 to 2 hours at room temperature to permit pre-diffusion, and then incubated for 48 hours at 25°C. After the incubation period, inhibition zones were measured and expressed in mm.
The zone of inhibition for the microemulsion formulations (ME II - ME X) varied from 31.13±0.18 to 39.03±0.32 mm. The concentration of the amount of drug diffused ranged from 18.36±1.26 to 36.39±1.27 \ig. The results indicated that all the microsomal formulations were effective in attaining minimum inhibitory concentration (MIC) value (14-42 ug/ml) of griseofulvin.
Table 1: Zone of inhibition and amount of drug diffused from various Table Remove
microemulsion formulations

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The zone of inhibition for ethosomes and ethosomal gels varied between 32.53±0.67 to 40.23±0.32 mm. The largest inhibition zone was observed for ET III (40.23 ± 0.32 mm) which contained combination of propylene glycol and Transcutol P. The concentration of the amount of drug diffused ranged from 20.73±1.31 to 40.37±1.27 \xg. The results indicated that all the ethosomal formulations were effective in attaining minimum inhibitory concentration (MIC) value (14-42 (ig/ml) of griseofulvin. It was also observed that when ethosomes were gelled with Carbopol, there was a decreased inhibition zone, which may be due to declined rate of diffusion of drug through gelled formulations (Table 2).
Table 2: Zone of inhibition and amount of drug diffused from various ethosomal formulations

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Example 30:
Skin sensitivity testing using griseofulvin microemulsions, ethosomes and
ethosomal gel compositions
Skin sensitivity testing was done by applying microemulsions (ME VI, ME VII and ME VIII) and ethosomal gel (ET Gel III) formulations to the skin using open patch test on 20 healthy human volunteers (Age 23-25 yrs) for 24 hours and observed for any
irritation, erythema, skin rash and edema for 24 hrs.
The study revealed that there was no sign of any redness, burning, irritation and swelling. Example 31: Clinical studies
The preliminary clinical investigations of microemulsions and ethosomal formulations in patients infected with fungal infections of different Tinea sp. revealed the efficacy of these topical dermal applications when compared with the conventional oral therapy of griseofulvin (Microfulvin Tab.). During the investigations it was observed that the patients reported symptomatic relief (i.e., subsided itching and burning sensation associated with fungal infections) with in 2-3 days of initiation of therapy. The total duration of therapy was also reduced (2-6 weeks as compared to 4-8 weeks with conventional oral therapy) which may be ascribed to the enhanced partitioning and localized targeting of the drug at the site of infection. Patient compliance was excellent as usually because of side effects patients generally discontinue the long 4-8 weeks conventional oral treatment regimen.
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.

We claim:
1. A colloidal composition of griseofulvin comprising 0.1% to 1.0% w/w of
griseofulvin, 1.0% to 30.0% w/w of a lipid or its derivative, 15.0% to 50.0% w/w of a surfactant, 1.0% to 20.0% w/w of a co-surfactant, 0.5% to 25% w/w of at least one penetration enhancer and 25% to 80% w/w of water.
2. The composition as claimed in claim 1, wherein the lipid or its derivative is selected from a group consisting of diesters of caprylic/capric acid, isopropyl myristate, isopropyl isostearate, isopropyl linoleate, isopropyl palmitate, medium chain triglycerides, oleic acid, palmitic acid, lauric acid, linoelaidic acid, linoleic acid, linolenic acid, glycolyzed ethoxylated glycerides of natural oils, lauric acid hexyl esters, or a mixture thereof.
3. The composition as claimed in claim 2, wherein the lipid or its derivative is either medium chain triglyceride of caprylic/capric acid or isopropyl myristate.
4. The composition as claimed in claim 1, wherein the surfactant is selected from a group consisting of polyglycolyzed glyceride, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene glycol ether, decaethylene glycol monododecyl ether, diethylene glycol monodecyl ether, ethylene glycol monoalkylalkyl ether, sorbitan ester, isopropyl alcohol, diethylene glycol monoethyl ether, phosphatidylcholine derivatives, lecithins, propylene glycol, polyethylene glycol, polyethylene oxide, polysorbate, polyglyeryl oleate, propylene glycol laurate, polyglycerol fatty acid ester, poloxamer, macrogol, or a mixture thereof.
5. The composition as claimed in claim 1, wherein the co-surfactant is selected from a group consisting of polyoxyethylene alcohol ester, isopropanol, sorbitan monooleate, glycerol, benzyl alcohol, 1-propanol, 1-butanol, 1-hexanol, 1-octanol, 1,2-alkanediols, 1,2-propanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, propylene glycol, polyethylene glycol, oleic esters of polyglycerol, ethyldiglycol, or mixture thereof.
6. A colloidal composition of griesofulvin comprising 0.1% to 1.0% w/w of griseofulvin, 0.5% to 10.0% w/w of at least one phospholipid, 0.1%-1% w/w of at least one sterol and 98.0- 99.0% w/w water.
7. A colloidal composition of griseofulvin comprising 0.1% to 1.0% w/w of griseofulvin, 0.5% to 10.0% w/w of at least one phospholipid, 0.5% to 25% w/w
of at least one penetration enhancer, 25% to 80% w/w of water and 10% to 50% w/w of at least an alcohol.
8. The composition as claimed in claim 6 or 7, wherein the phospholipid is selected from the group consisting of phosphatidyl choline, hydrogenated phosphatidyl choline, phosphatidic acid, soya phosphatidyl choline, egg phosphatidyl choline, dipalmityl phosphatidyl choline, distearyl phosphatidyl choline, phosphatidyl serine, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol, or mixtures thereof.
9. The composition as claimed in claim 6, wherein the sterol is selected from the group consisting of cholesterol, cholesterol oleate, cholesterol acetate, cholesterol palmitate, campesterol, P-sitosterol, l,2-dimyristoyl-.s77-glycero-3-phosphatidylcholine (DMPC), or a mixture thereof.
10. The composition as claimed in claim 7, wherein the alcohol is either ethanol or isopropyl alcohol or a mixture thereof.
11. The composition as claimed in any of the claims 1 to 10, wherein the composition is a topical formulation.
12. The composition as claimed in claim 11 wherein the topical formulation is in form of gel.
13. A process for preparing the composition as claimed in any of the claims 1 to 4, said process comprising providing a mixture of griseofulvin in the range of 0.1 % to 1.0 % w/w of the composition with oil phase ingredient in the range of 1.0 % to 30.0 % w/w of the composition, a surfactant in the range of 15.0 % to 50.0 % w/w of the composition, a co-surfactant in the range of 1.0 % to 20.0 % w/w of the composition, a penetration enhancer in the range of 0.5 % to 20.0 % w/w and aqueous phase in the range of 25.0 % to 80.0 % w/w of the composition.
14. A process for preparing the composition as claimed in any of the claims 5, 7 and 8, said process comprising providing a mixture of griseofulvin in the range of 0.1 % to 1.0 %w/w of the composition with a phospholipid in the range of 0.5 % to 10.0 % w/w of the composition, a sterol in the range of 0.1 % to 1.0 % w/w of the composition and aqueous phase in the range of 98.0 % to 99.0 % w/w of the composition.
15. A process for preparing the composition as claimed in any of the claims 5 to 7, said process comprising providing a mixture of griseofulvin in the range of 0.1
% to 1.0 % w/w of the composition with a phospholipid in the range of 0.5 % to 10.0 % w/w of the composition, an alcohol in the range of 10.0 % to 50.0 % w/w of the composition, a penetration enhancer in the range of 0.5 % to 25.0 % w/w and aqueous phase in the range of 25.0 % to 80.0 % w/w of the composition. 16. The composition as claimed in any of the claims 1 to 10, wherein the penetration enhancer is selected from a group consisting of N-methyl-2-pyrrolidone, hexyl-4-methyloxycarbonyl-2-pyrrolidone, 1 -hexyl-2-pyrrolidone, 1 -(2-hydroxyethyl)-pyrrolidone, 1 -lauryl-4-methyloxycarbonyl-2-pyrrolidone, poly (N-vinylpyrrolidone), menthol, peppermint oil, eucalyptus oil, cardamom oil, 1-carvone, cineole, eucalyptol, eugenol, nerolidol, Vitamin E (a-tocopherol), propylene glycol, phosphatidylcholine, lecithins, diethyl glycol monoethyl ether, alcohol, polyol, esters, surface active agents and phospholipids, or combination