Comparison of Diclofenac Diethylamine Permeation Across Horse Skin from Five Commercial Medical Human Formulations

The aim of this study was to compare the penetration of diclofenac through horse skin in vitro and its efficacy in vivo when applied from five, commercially available, human medical formulations containing 1.16% diclofenac diethylamine. The rate of transdermal penetration of diclofenac varied between formulations. Also, estimated steady-state flux (Jss) was significantly different from that reported for human and rat skin. All the tested formulations produced a very weak and short-lasting antiedematous effect.