Enhancing effects of fatty acids on piroxicam permeation through rat skins

To increase the skin permeation of piroxicam from the Poloxamer 407 gel, fa tty acid was added as a penetration enhancer to the Poloxamer 407 gel conta ining 1% piroxicam. The enhancing effects of the enhancer on the skin perme ation of piroxicam were evaluated using Franz diffusion cells fitted with i ntact excised rat skins. To elucidate the modes of the action of enhancers, thermal analysis and histological examinations were conducted. Among fatty acids tested linoleic acid showed the highest enhancing effects, with an e nhancement factor (EF) of 1.76. From the thermal analysis results, fatty ac ids have fluidizing effects on the stratum corneum. The skin pretreated wit h the Poloxamer 407 gels containing piroxicam including linoleic acid showe d a loosely layered stratum corneum and wide intercellular space.