A comparative permeation/release study of different testosterone gel formulations.
The major indication for testosterone (T) treatment is male hypogonadism that is characterized by low serum T concentrations. Although a recently developed hydroalcoholic gel, Androgel, containing 1% T addresses many of the problems associated with the more conventional formulations, the bioavailability of T is only 10% requiring 5 to 10 g of gel to be applied daily. The present study was performed to investigate the effect of isopropyl alcohol (IPA) content as a penetration enhancer based on its ability to prevent skin dryness and in turn to increase T permeation from hydroalcoholic gels. Five different hydroalcoholic gel formulations, containing 1% T and carbopol as the gel-forming polymer, were formulated by varying the amount of IPA. The release of T from each gel, including Androgel, was studied in vitro on Franz diffusion cells using cellulose ester and Celgard 2400 as synthetic membranes and hairless guinea pig skin as a natural membrane. The amount of drug released from the gels was analyzed using an HPLC-UV method. The results of release/permeation studies on guinea pig skin showed that all the gels were similar to Androgel, indicating that the addition of IPA does not affect the release of T from hydroalcoholic gels. Although no statistical significant difference was seen, the release profiles of the gels showed a trend of increasing release of T with increasing concentration of IPA. Thus, IPA does have a potential to increase the bioavailability of T from hydroalcoholic gels.
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Department of Biomedical and Pharmaceutical Sciences, School of Pharmacy University of Rhode Island, Kingston, Rhode Island, USA.
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Hossein
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D019840:2-Propanol; D000279:Administration, Cutaneous; D000704:Analysis of Variance; D000728:Androgens / Q000737:chemistry / Q000493:pharmacokinetics*; D000818:Animals; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D016503:Drug Delivery Systems; D005782:Gels; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008567:Membranes, Artificial; D010539:Permeability; D010592:Pharmaceutic Aids; D012869:Skin Absorption; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D013739:Testosterone / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*
D000728:Androgens; D005782:Gels; D008567:Membranes, Artificial; D010592:Pharmaceutic Aids; D012997:Solvents; D013739:Testosterone; D019840:2-Propanol