Abstract:
A topical, foamable composition is provided that includes at least one antifungal agent that is able to penetrate the upper layers of skin and is retained in or on an area to be treated for a prolonged period of time, and that has a residual non-volatile component content less than 25%. In addition, a method of treating fungal diseases including jock itch, tinea, dandruff and sebborheic dermatitis is provided, and includes applying to the affected area of patient requiring such treatment an antifungal composition.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a foamable antifungal composition for the treatment of various skin conditions. 
         [0002]    Antifungal agents are well known, and include macrolide antibiotics such as griseofulvin, and imidazoles such as clotrimazole and ketoconazole. 
         [0003]    Ketoconazole was originally described by Heeres et al in U.S. Pat. No. 4,335,125, in which its principal utility was an antifungal compound useful in the treatment of a variety of conditions including sebborheic dermatitis, dandruff, “jock itch” and tinea. 
         [0004]    Antifungal compositions are traditionally applied as lotions or creams. There are however disadvantages to these forms. In particular, the formulations are frequently very viscous requiring substantial rubbing to achieve penetration into the effected area, an act in itself which causes discomfort and sometimes irritation. If the viscous formulations are not vigorously applied, the active antifungal agent does not necessarily reach the site requiring treatment being the epidermis of the skin. Non-viscous creams and lotions are wont to flow off the effected site before penetration is achieved. One final disadvantage is that cream and lotion bases in themselves can add to site irritation depending on their content. 
         [0005]    Ketoconazole was disclosed in U.S. Pat. No. 4,569,935 to be useful in the topical treatment of psoriasis and seborrheic dermatitis. Pursuant to this utility, ketoconazole has been marketed in a 2% shampoo formulation for the treatment of scaling due to dandruff, sold under the brand name “Nizoral®”. This shampoo is applied by the user and then removed shortly, for example 3-5 minutes, after its application by rinsing with water. The active agent is thus only in contact with the area to be treated for a very limited time. 
         [0006]    Another patent describing ketoconazole based shampoos is U.S. Pat. No. 5,456,851 in the name of JOHNSON &amp; JOHNSON CONSUMER PRODUCTS, INC which aims to provide good cosmetic properties to the shampoo including lather, and to retard degradation of the ketoconazole. This composition is a foaming formulation. 
         [0007]    The disadvantage of such shampoo formulations is that during normal usage, the formulation does not remain on the scalp for a period of time sufficient to allow the antifungal agent to achieve its maximal therapeutic effect since they are designed to be applied, for example in the shower or bath, and shortly after rinsed off with water. Typically, the application instructions for such shampoos suggest that the formulation be removed after 3-5 minutes. 
         [0008]    In order to achieve maximal therapeutic effect, one alternative such as is described in AU 80257/87, is to provide a high quantity of residual solids which remain after application to treat the offending skin condition. There is disclosed in AU 80257/87 a foam composition for the delivery of minoxidil. The formulations disclosed in this document all contain a high percentage of non-volatile residues, including propylene glycol. While it is not disclosed why these formulations contain such a large amount of propylene glycol, it is postulated that the propylene glycol is probably required either to enhance the penetration and/or to improve the solubility of the minoxidil. The disadvantage of a composition with a high residual content is that the non-volatile residues are retained at the site of application and therefore feel unpleasant and unattractive to the user. 
         [0009]    Alternatives to ketoconazole and minoxidil are described in AU-A-35717/93 in the name of SMITH KLINE BEECHAM PLC which discloses compositions including a novel androstene steroid for use in the treatment of acne and sebborrhea, and AU-A-48851/96 in the name of MEDEVA PLC which describes the use of betamethasone in a quick breaking foam including a buffering agent for use in the treatment of skin diseases and particularly scalp psoriasis. 
         [0010]    It is an aim of this invention to provide an antifungal composition which is effective in its treatment of fungal skin conditions but which is also pleasant to use. 
       SUMMARY OF THE INVENTION 
       [0011]    To this end, in a first aspect of the invention, there is provided a topical, foamable composition including at least one antifungal agent, said composition characterised in that said at least one antifungal agent is able to penetrate the upper layers of the skin and is retained in or on an area to be treated for a prolonged period of time, and in that it has a residual non-volatile component content of less that 25%. 
         [0012]    It has been surprisingly found that the antifungal composition of the present invention has a commercially acceptable cosmetic appeal and during normal usage allows greater penetration and retention of the antifungal agent in the upper layers of the skin, particularly in the epidermis, thus providing a reservoir of active agent available to achieve a sustained antifungal effect when compared against known formulations. This latter feature leads to enhanced pharmaceutical appeal as well as cosmetic appeal. Moreover, the residual solids content of the formulation is so low as to not provide discomfort and irritation to the user 
         [0013]    The term “prolonged period of time” is meant to encompass periods of time sufficiently long so as to enable the active agent present to be substantially fully absorbed by the organism being treated, or substantially fully metabolised by the patient being treated. 
         [0014]    In a preferred embodiment, the one or more antifungal agents is selected from the group consisting of diols, allylamines (including naftifine and terbinafine), polyene macrolide antibiotics (including amphotericin and nystatin), triazole derivatives (such as fluconazole), fatty acids (such as caprylic and propionic acid), amorolfine, ciclopirox, olamine, benzoic acid, flucytosine, haloprogin, tolnaftate, undecenoic acid and its salts, griseofulvin and imidazole compounds. More preferably, the antifungal is an imidazole compound. Most preferably, the antifungal agent is ketoconazole or chlorphenesin (3-(4-Chlorphenoxy)propane-1,2-diol). 
         [0015]    Preferably the compositions according to the invention have a residual non-volatile component content of less that 10%, and more preferably of less than 6%. 
         [0016]    In a preferred embodiment the topical, foamable composition is provided as a mousse. 
         [0017]    in a further preferred embodiment the mousse is a temperature sensitive mousse, which breaks down rapidly when exposed to the skin temperature. 
         [0018]    In a still further embodiment, the composition is an ethanolic mousse including a lower alcohol content of greater than 10%, more preferably greater than 50% and a hydrocarbon gas content propellent of less than 60%, more preferably less than 10%. 
         [0019]    In an alternative embodiment the composition is an aqueous mousse including no lower alcohol content and a hydrocarbon gas content propellent of less than 60%, more preferably less than 10%. 
         [0020]    (Unless specified otherwise in the specification, all % are based on the total weight of the composition.) 
         [0021]    In the temperature sensitive mousse, the long chain alcohol may be chosen from, for example, cetyl, stearyl, lauryl, myristyl and palmityl alcohols and mixtures of two or more thereof. 
         [0022]    The lower alcohol may preferably be chosen from methyl, ethyl, isopropyl and butyl alcohols, and mixtures of two or more thereof. Ethanol has been found to be particularly preferred. 
         [0023]    Surfactants utilised in the temperature sensitive mousse may preferably be chosen from ethoxylated sorbitan stearate, palmitate, oleate, nonyl phenol ethoxylates and fatty alcohol ethoxylates, and mixtures of two or more thereof. Thus, for example, Polysorbate 60 (a mixture of partial stearic esters of sorbitol and its anhydrides copolymerised with approximately 20 moles of ethylene oxide for each mole of sorbitol and its anhydrides) has been found to be particularly preferred. The surfactant enhances the long chain alcohol solubility in the system and enhances mousse formation. 
         [0024]    In a further aspect of the invention, there is provided a foamable composition including 
         [0000]    up to 5% of long chain alcohols
 
up to 5% of quaternary compound
 
up to 10% of propylene glycol
 
up to 5% of antifungal agent
 
up to 90% of lower alcohol solvent
 
up to 5% of surfactant
 
5-95% of water, and
 
up to 20% of a hydrocarbon gas propellant
 
         [0025]    Preferably, the long chain alcohol is cetyl or stearyl alcohol or mixtures thereof. 
         [0026]    Preferably, the quaternary compound is quaternium oxy ethyl alkyl ammonium phosphate commercially available under the trade name, Dehyquart SP. 
         [0027]    Preferably, the lower alcohol solvent is ethanol or propanol or mixtures thereof. 
         [0028]    Suitable gas propellants include non-toxic gas propellants suited to foamable cosmetic and pharmaceutical compositions and known to those skilled in the art. 
         [0029]    Thus, one may select the propellant from propane, butane, dichloro difluoro methane, dichloro tetrafluoro ethane, octafluoro cyclobutane, and mixtures of two or more thereof. It is necessary to select a propellant most compatible with the entire system. The maximum level of propellant will be determined as the amount miscible with the utilized water/lower alcohol ratio. In addition to acting as a propellant, the propellant will also act as a solvent for the long chain alcohol and active substances in the aqueous/alcoholic system. 
         [0030]    In a second aspect of the invention there is provided a composition for the treatment of fungal skin conditions including dandruff, seborrheic dermatitis, tinea, jock itch and the like, said composition characterised in that it is a foamable mousse applicable to the skin of the user in the substantial absence of water and without substantially immediate removal by washing. 
         [0031]    In a preferred embodiment of this aspect of the invention, said composition has a non-volatile component content of less than 25%, preferably less than 10% and more preferably less than 6%. 
         [0032]    In a more preferred embodiment of this aspect of the invention, the mousse is a temperature sensitive mousse, which breaks down rapidly when exposed to the skin temperature. 
         [0033]    In a still further preferred embodiment, the composition is a mousse including a lower alcohol content of greater than 10%, more preferably greater than 50% and a hydrocarbon gas content propellent of less than 60%, more preferably less than 10%. 
         [0034]    In a further aspect of the invention there is provided a topical, foamable composition including an antifungal agent characterised in that upon application to the skin of a user a penetration of at feast 10 μg/cm 2  is achieved in the epidermis within one hour of application and sustained over a period of at least 23 hours. 
         [0035]    When the preferred active agent is ketoconazole, the invention provides a topical, foamable composition characterised in that upon application to the skin of a user a penetration of at least 30 μg/cm 2  is achieved in the epidermis within one hour of application and sustained over a period of at least 23 hours. 
         [0036]    When the preferred active agent is chlorphenesin, the invention provides a topical, foamable composition characterised in that upon application to the skin of a user a penetration of at least 10 μg/cm 2  is achieved in the epidermis within one hour of application and sustained over a period of at least 23 hours. 
         [0037]    In a still further aspect of the invention, there is provided a method of treating fungal infections, particularly tinea, jock itch, dandruff and sebborheic dermatitis by applying to the affected area of a patient requiring such treatment the antifungal composition of the present invention. 
         [0038]    In a preferred embodiment of this aspect of the invention, the composition is allowed to remain on the affected area for an extended period of time. 
         [0039]    In this context “extended period of time” means a length of time greater than the length of time that prior art topical compositions such as shampoos are prescribed to remain in contact with the affected area. Usually, shampoos are designed to be washed off within 5 minutes. 
         [0040]    More preferably, when the composition is used to treat dandruff or sebborheic dermatitis, it is applied at one wash or between washes and is allowed to remain on the site of application such as the scalp or hair until the site of application is subsequently washed again. 
         [0041]    The invention also encompasses the use of an antifungal agent in the preparation of a topical foamable composition for the treatment of fungal diseases including dandruff, tinea, jock itch and sebborheic dermatitis, the topical foamable composition being characterised in that it is able to penetrate the epidermis of the skin and is retained in or on an area to be treated for a prolonged period of time, and in that it has a non-volatile component content of less that 25%. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0042]    Two formulations of the present invention were prepared. 
         [0043]    1) 0.5% ketoconazole mousse composition 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Cetyl alcohol 
                 1.10 
               
               
                   
                 Stearyl alcohol 
                 0.50 
               
               
                   
                 Quaternium 52 (50%) 
                 1.00 
               
               
                   
                 Propylene Glycol 
                 2.00 
               
               
                   
                 Ketoconazole USP 
                 0.50 
               
               
                   
                 Ethanol 95PGF3 
                 60.55 
               
               
                   
                 Deionised Water 
                 30.05 
               
               
                   
                 P75 Hydrocarbon Propellant 
                 4.30 
               
               
                   
                   
               
             
          
         
       
     
         [0044]    2) 1% ketoconazole mousse composition 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Cetyl alcohol 
                 1.10 
               
               
                   
                 Stearyl alcohol 
                 0.50 
               
               
                   
                 Quaternium 52 (50%) 
                 1.00 
               
               
                   
                 Propylene Glycol 
                 2.00 
               
               
                   
                 Ketoconazole USP 
                 1.00 
               
               
                   
                 Ethanol 95PGF3 
                 60.20 
               
               
                   
                 Deionised Water 
                 29.90 
               
               
                   
                 P75 Hydrocarbon Propellant 
                 4.30 
               
               
                   
                   
               
             
          
         
       
     
         [0045]    The compositions were prepared by dissolving the active in the ethanol. the cetyl and stearyl alcohol are then added to the heated solution and mixed until dissolved. The quaternium 52, propylene glycol and water are then added and stirred until homogenous, while maintaining the elevated temperature. The solution is then dispensed into aerosol cans where the aerosol valve is then fitted and the can charged with propellant. 
       Example 1 
       [0046]    A study was undertaken to compare the epidermal penetration of the two mousse compositions above, against the commercially available Nizoral® shampoo containing 2% ketoconazole. In particular the respective formulations were applied and removed as for a conventional shampoo so as to compare the penetration of the respective formulations into the epidermis. 
       Equipment and Materials 
       [0047]    in vitro Franz diffusion cells (surface area 1.33 cm 2 , receptor volume 3.5 ml) incorporating human epidermis 
         [0048]    HPLC equipment: Shimadzu automated HPLC system with uv detector, bovine serum albumin dissolved in phosphate buffered saline (pH 7.4) as receptor phase to mimic physiological conditions. 
       Experimental Protocol 
       [0049]    finite dosing (50 mg for shampoo and 100 mg for mousses) 
         [0050]    receptor phase: 4% BSA in phosphate buffered saline at pH 7.4 sampling time: 6, 10, 24 hours (amount in receptor phase (μg/cell) and epidermis (μg/cell)) non-occlusion study 
         [0051]    each time period and formulation conducted in triplicate. 
       Application Procedure 
       [0000]    
       
         Shampoo: 50 mg shampoo (equivalent to 1 mg ketoconazole)
       dose applied to pre-wetted skin with stirring and rinsed off with deionised water after 4 minutes.   
     
         Mousse: 100 mg mousse (equivalent to 1 mg ketoconazole for 1% mousse and 500 μg ketoconazole for 0.5% mousse
       dose applied (not rinsed off).   
     
       
     
       Epidermal Retention Protocol 
       [0056]    Epidermis removed from cell following time interval, rinsed with distilled water and dried to remove ketoconazole remaining on surface. Ketoconazole extracted from epidermal sample by soaking in methanol for 1 hour. This procedure is repeated with a second volume of methanol for 30 mins. The methanol samples are combined for HPLC analysis (this procedure has been validated with a 99% recovery rate). 
       HPLC Assay 
       [0057]    Column: Nova Pak C 18  steel column, 3.9×150 mm
 
Mobile phase: 70% MeOH in 0.02 M phosphate buffer, pH 6.8
 
       Wavelength: 254 nm 
       [0058]    Flow rate: 1.3 ml/min
 
Injection volume: 10
 
Retention time: about 7 min
 
         [0059]    Results 
         [0060]    Table 1 shows the cumulated ketoconazole in both the receptor phase and the epidermis at defined time points following application of the mousse according to the invention and the shampoo of the prior art. 
         [0000]    
       
         
               
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Ketoconazole μg/cell 
               
             
          
           
               
                   
                 6 hours 
                 10 hours 
                 24 hours 
               
             
          
           
               
                 Sample 
                 receptor 
                 epidermis 
                 receptor 
                 epidermis 
                 receptor 
                 epidermis 
               
               
                   
               
             
          
           
               
                 0.5% mousse 
                 4.96 
                 33.15 
                 9.04 
                 69.46 
                 14.69 
                 42.10 
               
               
                 0.5% mousse 
                 2.83 
                 35.71 
                 18.06 
                 48.04 
                 24.77 
                 39.19 
               
               
                 0.5% mousse 
                 14.37 
                 34.3 
                 21.3 
                 55.29 
                 9.82 
                 48.27 
               
               
                 Mean ± SD 
                 7.4 ± 6.1 
                 34.4 ± 1.3  
                 16.1 ± 6.4  
                 57.6 ± 10.9 
                 16.4 ± 7.6  
                 43.2 ± 4.6 
               
               
                   1% mousse 
                 12.86 
                 46.4 
                 31.50 
                 67.51 
                 21.90 
                 51.43 
               
               
                   1% mousse 
                 10.03 
                 61.8 
                 11.05 
                 55.65 
                 35.85 
                 46.64 
               
               
                   1% mousse 
                 18.61 
                 38.6 
                 19.38 
                 56.83 
                 10.72 
                 43.28 
               
               
                 Mean ± SD 
                 13.8 ± 4.4   
                 48.9 ± 11.8 
                 20.6 ± 10.3 
                  60 ± 6.5 
                 22.8 ± 12.6 
                 47.1 ± 4.1 
               
               
                   2% shampoo 
                 N 
                 N 
                 N 
                 0.89 
                 N 
                 N 
               
               
                   2% shampoo 
                 N 
                 N 
                 N 
                 0.28 
                 N 
                 0.38 
               
               
                   2% shampoo 
                 N 
                 N 
                 N 
                 N 
                 N 
                 0.34 
               
               
                 Mean ± SD 
                 — 
                 — 
                 — 
                 0.39 ± 0.46 
                 — 
                  0.24 ± 0.21 
               
               
                   
               
               
                 N: not detectable (assuming to be zero for calculating mean and SD) 
               
               
                 —: not available 
               
             
          
         
       
     
         [0061]    Table 2 shows the cumulated ketoconazole in both receptor (expressed as μg/ml receptor fluid) and epidermis (expressed as μg/cm 2  surface area) at defined time points following application of the mousse according to the present invention and the shampoo of the prior art. 
         [0000]    
       
         
               
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
             
             
               
                   
                   
               
               
                   
                 Ketoconazole μg 
               
             
          
           
               
                   
                 6 hours 
                 10 hours 
                 24 hours 
               
             
          
           
               
                 Sample 
                 receptor 
                 epidermis 
                 receptor 
                 epidermis 
                 receptor 
                 epidermis 
               
               
                   
               
               
                 0.5% mousse 
                 1.42 
                 26.95 
                 2.58 
                 56.47 
                 4.20 
                 34.23 
               
               
                 0.5% mousse 
                 0.81 
                 29.03 
                 5.46 
                 39.06 
                 7.08 
                 31.86 
               
               
                 0.5% mousse 
                 4.11 
                 27.89 
                 6.09 
                 44.95 
                 2.81 
                 39.24 
               
               
                 Mean ± SD 
                 2.11 ± 1.76 
                 27.96 ± 1.04 
                 4.61 ± 1.82 
                 46.83 ± 8.86 
                 4.70 ± 2.18 
                 35.11 ± 3.77 
               
               
                   1% mousse 
                 3.67 
                 37.72 
                 9.00 
                 54.89 
                 6.26 
                 41.81 
               
               
                   1% mousse 
                 2.87 
                 50.24 
                 3.16 
                 45.24 
                 10.24  
                 37.92 
               
               
                   1% mousse 
                 5.32 
                 31.38 
                 5.54 
                 46.20 
                 3.06 
                 35.19 
               
               
                 Mean ± SD 
                 3.95 ± 1.25 
                 39.78 ± 9.60 
                 5.90 ± 2.94 
                 48.78 ± 5.31 
                 8.52 ± 3.60 
                 38.31 ± 3.33 
               
               
                   2% shampoo 
                 N 
                 N 
                 N 
                  0.72 
                 N 
                 N 
               
               
                   2% shampoo 
                 N 
                 N 
                 N 
                  0.23 
                 N 
                  0.31 
               
               
                   2% shampoo 
                 N 
                 N 
                 N 
                 N 
                 N 
                  0.28 
               
               
                 Mean ± SD 
                 — 
                 — 
                 — 
                  0.32 ± 0.37 
                 — 
                  0.20 ± 0.17 
               
               
                   
               
               
                 N: not detectable (assuming to be zero for calculating mean and SD) 
               
               
                 —: not available 
               
             
          
         
       
     
         [0062]      FIG. 1  shows the time course of the ketoconazole penetrating across human epidermis to receptor fluid. The closed points of the graph represent 0.5% mousse, the open points represent 1.0% mousse. Data are the mean±SD of triplicate (from Table 2). 
         [0063]      FIG. 2  represents the time course of ketoconazole retained in the epidermis. The closed points of the graph represent 0.5% mousse, the open points represent 1.0% mousse. Data are the mean±SD of triplicate (from Table 2). 
         [0064]      FIG. 3  compares the levels of retention of ketoconazole on the skin, the levels of retention of the ketoconazole in the skin and the amount of ketoconazole passed through the skin in the tests using a mousse according to the invention with the same measures using Nizoral®. Note that ketoconazole levels found after application of the Nizoral® shampoo were low and thus are not visible in this figure 
         [0065]    It can readily be observed from the results of example 1 that:
   1. the ketoconazole in the mousse compositions of the present invention penetrated the skin in appreciable quantity;   2. the ketoconazole in the mousse composition of the present invention was preferentially retained in the epidermis compared to penetration into the receptor solution;   3. application of the prior art shampoo, Nizoral®, resulted in insignificant amounts of ketoconazole in the epidermis and penetrating to the receptor phase at any of the time points following application using a standardised shampooing procedure;   4. comparison of the 1% and 0.5% mousse formulations of the present invention shows that there is little difference in epidermal and receptor phase concentrations.   
 
       Example 2 
       [0070]    A second study was undertaken to compare the skin penetration and retention of ketoconazole from the 1% ketoconazole mousse composition of the current invention with Nizoral® Shampoo (1% w/w). The 1% mousse composition had a total residue content of 5.1% solids including active. 
       Equipment and Materials 
       [0071]    In vitro Franz diffusion cells (surface area 1.33 cm 2 , receptor volume 3.5 mL) incorporating full thickness human skin, 
         [0000]    HPLC equipment: Shimadzu automated HPLC system with uv detector. 
       Experimental Protocol 
       [0072]    Finite dosing (50 mg of each formulation placed onto skin surface), Receptor phase: 4% bovine serum albumin (BSA) in phosphate buffered saline (PBS) pH 7.4, 
         [0000]    Sampling times for skin retention: 15 minutes, 1, 12, 24 hours,
 
Sampling times for skin penetration to receptor phase: 12, 24 hours,
 
Amount of ketoconazole in full thickness skin and receptor phase measured by HPLC assay following suitable extraction procedure,
 
Non-occlusion study,
 
Triplicate measurements.
 
       Application Procedure 
       [0073]    Both mousse and shampoo were applied and left in contact with the skin for the duration of the penetration study. Following this the formulation was washed off the skin with distilled water prior to sample extraction procedure and HPLC assay for ketoconazole content. 
       HPLC Assay 
       [0074]    Column: Nova Pac C 18  steel column, 3.9×150 mm (Waters)
 
Mobile phase: 70% MeOH in 0.02M PBS, pH 6.8
 
       Wavelength: 254 nm 
       [0075]    Flow rate: 1.0 mL/min
 
Injection volume: 10
 
Retention time: approximately 8 mins
 
       Full Thickness Ship Retention Protocol 
       [0076]    Full thickness skin was removed from cell following time interval, rinsed with distilled water and dried to remove ketoconazole remaining on surface. Ketoconazole was extracted from full thickness skin sample by soaking in methanol for 1 hour. This procedure was repeated with a second volume of methanol for 30 mins. The methanol samples were combined from HPLC analysis. [This procedure has been validated with a 99% recovery rate]. 
       Results 
       [0077]      FIG. 4  shows the HPLC standard curve for ketoconazole. 
         [0078]    Table 3 shows the amount of ketoconazole retained in the skin (μg/cm 2 ) at 15, 60 minutes, 12 and 24 hours following application of the mousse according to the invention, or the shampoo of the prior art. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Ketoconazole retained in skin (μg/cm 2 ) at 15, 60 mins, 12, 24 hours 
               
               
                 following application of mousse or shampoo. 
               
             
          
           
               
                   
                 Ketoconazole in skin (μg/cm 2 ) 
               
               
                   
                 mean ± SEM 
               
             
          
           
               
                 Sample 
                 15 mins 
                 60 mins 
                 12 hrs 
                 24 hrs 
               
               
                   
               
               
                 Shampoo 
                 11.2 ± 0.91 
                 24.2 ± 1.58 
                  39.7 ± 12.3 
                  70.1 ± 18.8 
               
               
                 Mousse 
                 19.6 ± 2.5  
                 44.1 ± 8.27 
                 128.37 ± 19.1 
                 228.57 ± 14.8 
               
               
                   
               
             
          
         
       
     
         [0079]    Table 4 shows the amount of ketoconazole penetrated to the receptor phase (μg/mL) at 12, 24 hours following application of the mousse according to the invention, or the shampoo of the prior art. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Ketoconazole penetrated to receptor phase (μg/mL) at 12, 24 hours 
               
               
                 following application of mousse or shampoo. 
               
             
          
           
               
                   
                 Ketoconazole in receptor (μg/mL) 
                   
               
               
                   
                 mean ± SEM 
               
             
          
           
               
                   
                 Sample 
                 15 mins 
                 60 mins 
                 12 hrs 
                 24 hrs 
               
               
                   
                   
               
               
                   
                 Shampoo 
                 — 
                 — 
                 n 
                 0.04 ± 0.04 
               
               
                   
                 Mousse 
                 — 
                 — 
                 0.07 ± 0.05 
                 0.30 ± 0.04 
               
               
                   
                   
               
               
                   
                 n: not detectable 
               
               
                   
                 —: not assayed 
               
             
          
         
       
     
         [0080]      FIG. 5  shows the amount of ketoconazole retained in the skin versus the time after application of the formulation according to the invention. Data are the mean±SEM (n=3) from Table 4. 
         [0081]    The mousse formulation according to the invention demonstrated significantly greater skin retention of ketoconazole than the shampoo formulation of the prior art over the 24 hour period. 
         [0082]    It can readily be observed from the results of example 2 that:
   1. penetration of ketoconazole to the receptor phase over the 24 hours following application was minimal for both shampoo and mousse.   2. skin retention of ketoconazole was significantly greater following application of the mousse formulation compared to the shampoo (p&lt;0.05).   
 
       Example 3 
       [0085]    A third study was undertaken to compare the skin penetration and retention of two formulations according to the invention in which the active anti fungal agent was chlorphenesin (0.5% w/w). One formulation was ethanolic and had a total residue content of 2.5% solids including active, the other formulation was aqueous and had a total residue content of 4.6% solids including active. 
         [0000]    
       
         
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 % w/w 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Aqueous formulation 
                   
               
               
                   
                 Chlorphenesin 
                 0.50 
               
               
                   
                 Cetyl alcohol 
                 0.70 
               
               
                   
                 Stearyl alcohol 
                 0.30 
               
               
                   
                 Icocetyl alcohol 
                 2.50 
               
               
                   
                 Ceteth 20 
                 0.50 
               
               
                   
                 Preservative 
                 0.10 
               
               
                   
                 Purified Water 
                 90.40 
               
               
                   
                 P75 Hydrocarbon Propellant 
                 5.00 
               
               
                   
                 Ethanolic formulation 
               
               
                   
                 Chlorphenesin 
                 0.50 
               
               
                   
                 Cetyl alcohol 
                 1.10 
               
               
                   
                 Stearyl alcohol 
                 0.50 
               
               
                   
                 Polysorbate 
                 0.40 
               
               
                   
                 Ethanol 95% 
                 60.79 
               
               
                   
                 Purified Water 
                 32.41 
               
               
                   
                 P75 Hydrocarbon Propellant 
                 4.30 
               
               
                   
                   
               
             
          
         
       
     
       Equipment and Materials 
       [0086]    In vitro Franz diffusion cells (surface area 1.33 cm 2 , receptor volume 3.5 mL) incorporating full thickness human skin, 
         [0000]    HPLC equipment: Shimadzu automated HPLC system with uv detector. 
       Experimental Protocol 
       [0087]    Finite dosing (50 mg of each formulation placed onto skin surface), 
         [0000]    Receptor phase: 4% bovine serum albumin (BSA) in phosphate buffered saline (PBS) pH 7.4,
 
Sampling times for skin retention: 15 minutes, 1, 12, 24 hours,
 
Sampling times for skin penetration to receptor phase: 12, 24 hours,
 
Amount of chlorphenesin in full thickness skin and receptor phase measured by HPLC assay following extraction into acetonitrile (ACN) and methanol (MeOH) (9:1),
 
Non-occlusion study,
 
Triplicate measurements.
 
       Application 
       [0088]    Mousses according to the invention were applied and left in contact with the skin for the duration of the penetration study. Following this the formulation was washed off with distilled water prior to the extraction and HPLC for chlorphenesin content. 
       HPLC Assay 
       [0089]    Column: Nova Pac C 18  steel column, 3.9×150 mm (Waters)
 
Mobile phase: 30% ACN
 
       Wavelength: 280 nm 
       [0090]    Flow rate: 1.0 mL/min
 
Injection volume: 20 μL
 
Retention time: approximately 3.6 mins
 
       Skin Retention Protocol 
       [0091]    Skin was removed form the cell following time interval and rinsed with distilled water to remove chlorphenesin on the surface. Chlorphenesin was extracted from homogenised skin by soaking in 1 mL ACN-MeOH mix for 1 hour. This procedure was repeated for a further four 30 minute periods. The five samples were combined for HPLC analysis. [The procedure was validated with a 99% recovery rate]. 
       Results 
       [0092]      FIG. 6  shows the HPLC standard curve for chlorphenesin. Data are the mean±standard deviation (n=3). 
         [0093]    Table 5 shows the amount of chlorphenesin retained in the skin (μg/cm 2 ) at 15, 60 minutes, 12 and 24 hours following application of the mousse according to the invention. 
         [0000]    
       
         
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 5 
               
             
             
               
                   
                   
               
               
                   
                 Chlorphenesin in skin (μg/cm 2 ) 
               
               
                   
                 mean ± SD 
               
             
          
           
               
                 Sample 
                 15 mins 
                 60 mins 
                 12 hrs 
                 24 hrs 
               
               
                   
               
               
                 aqueous 
                 12.8 ± 4.8 
                 13.2 ± 1.1 
                 47.6 ± 13.2 
                 35.8 ± 2.2  
               
               
                 non-aqueous 
                 16.7 ± 5.5 
                   22 ± 9.7 
                 93.8 ± 17.3 
                 57.4 ± 20.4 
               
               
                   
               
             
          
         
       
     
         [0094]    Table 6 shows the amount of chlorphenesin penetrated to the receptor phase (μg/mL) at 12, 24 hours following application of the mousse according to the invention. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 6 
               
             
             
               
                   
                   
               
               
                   
                 Chlorphenesin in receptor (μg/mL) 
                   
               
               
                   
                 mean ± SD 
               
             
          
           
               
                   
                 Sample 
                 15 mins 
                 60 mins 
                 12 hrs 
                 24 hrs 
               
               
                   
                   
               
               
                   
                 aqueous 
                 — 
                 — 
                 2.9 ± 0.4 
                 5.6 ± 1.1 
               
               
                   
                 non-aqueous 
                 — 
                 — 
                   5 ± 0.7 
                 5.1 ± 1.5 
               
               
                   
                   
               
               
                   
                 — not assayed 
               
             
          
         
       
     
         [0095]      FIG. 7  shows the amount of chlorphenesin retained in the skin versus the time after application of the formulation according to the invention. Data are the mean±standard deviation (n=3) from Table 5. The open points are the aqueous formulation. The closed points represent the ethanolic formulation. 
         [0096]    It is readily observed from the results of example 3 that active agents other than ketoconazole formulated as both ethanolic and aqueous compositions achieve the desired penetration and retention levels for effective treatment of fungal skin conditions. 
         [0097]    It will be appreciated that the scope of this invention goes beyond the specific formulations exemplified to encompass topical foamable antifungal compositions having like components to those specifically mentioned but having characteristic penetration and retention levels in the skin of the user, and low levels of residual solid content as defined.