Percutaneous transport of diclofenac sodium from mixtures of fatty alcohol(or fatty acid) and propylene glycol through the rabbit abdominal skin

Diclofenac sodium is a nonsteroidal anti-inflammatory drug with analgesic, antipyretic, and anti-inflammatory activity. When used in a topical applica tion, diclofenac can diffuse through the skin and into the subcutaneous tis sue to effect the anti-inflammatory action. In this study, in vitro evaluat ions of the percutaneous transport of diclofenac sodium in various bases co ntaining fatty alcohols/propylene glycol or fatty acid/propylene glycol mix tures through the abdominal skin of the rabbit were investigated. Results s how that the transdermal flux of diclofenac sodium in the fatty alcohol/pro pylene glycol bases of the same ratio is affected by the chain length of th e fatty alcohol, and its effect is in the order of C-10 > C-12 > C-14 > C-1 8. However, the transdermal flux of diclofenac sodium in the fatty acid/pro pylene glycol bases of the same ratio is also affected by the chain length of the fatty acid but no absolute relationship was found. For the same chai n length of fatty acid and fatty alcohol used in the formulation base that was otherwise the same, the transdermal flux of diclofenac sodium is higher in the formula containing fatty alcohol than that containing fatty acid.