Enhancement of skin penetration of nonsteroidal anti-inflammatory drugs from extemporaneously compounded topical-gel formulations.

Ketoprofen and ibuprofen topical gels were compounded with decyl methyl sulfoxide and the terpenes d-limonene, (-)-menthone, terpinen-4-ol, and a-terpineol as penetration enhancers. Transdermal penetration profiles for both ketoprofen and ibuprofen were determined using full-thickness human skin, modified Franz diffusion cells and an isotonic (pH7.4) phosphate buffer solution. Human skin was used in these experiments to approximate the therapeutic use of these gels. Ibuprofen was found to have superior transdermal kinetics when compared to ketoprofen. Ibuprofen is a smaller and more lipophilic molecule than ketoprofen, which gives it better penetration properties. All enhancers tested significantly increased the penetration (except (-)-menthone) and skin retention (except terpinen-4-ol) of ketoprofen. None of the enhancers tested significantly increased the penetration or retention of ibuprofen. Despite the lack of enhancer activity, ibuprofen still demonstrated higher skin penetration and retention than enhanced delivery of ketoproen. The results of these studies suggest that the addition of penetration enhancers can significantly increase the amount of ketoprofen penetration, while enhancers demonstrated no significant increase (and can actually decrease) the amount of ibuprofen penetrating into and through the skin.