Topical delivery Penetration enhancers Skin

Davis AF, Hadgraft J. Supersaturated solutions as topical drug delivery systems. In Walters KA, Hadgraft J, eds. Pharmaceutical Skin Penetration Enhancement. New York Marcel Dekker, 1993 243-268. 

Murakami T, Yoshioka M, Yumoto R. Topical delivery of keloid therapeutic drug, tranilast, by combined use of oleic acid and propylene glycol as a penetration enhancer evaluation by skin microdialysis in rats. J Pharm Pharmacol 1998 50 49—54. 

There is a paucity of published data on in vitro studies of dermal penetration in food animals. In one study comparing the effects of freezing on human and cow skin (27), it is alluded to that the follicular route of penetration predominates in the cow. These authors have also written an excellent review on topical drug delivery to cattle and sheep which should be consulted for further details (2S). In this work, studies on the dermal application of twenty four different substances are reviewed. Some interesting data on differential effects of dermal enhancers in different species underlines the problems inherent to interspecies extrapolations. One conclusion of this study was that "the barrier properties of sheep and cattle skin are not well understood." This situation has not improved in the intervening years. 

---