Influence of phloretin and 6-ketocholestanol on the permeation of progesterone through porcine skin.

In this study the effect of phloretin (PH) and 6-ketocholestanol (KC) on the permeation of progesterone through porcine skin has been examined. Both PH and KC were incorporated into unilamellar L-alpha-phosphatidylcholine (PC) liposomes at different concentrations (7.5, 15, 30 and 60 mol%). In diffusion experiments with porcine skin, both substances, to a different degree, enhanced the steady state flux of progesterone. It was increased up to 2.4-fold using 15 mol% KC, and 1.4-fold using 30 mol% PH. The results indicate an interaction of these two compounds with the lipid components of the stratum corneum. In order to visualise the interaction, differential scanning calorimetry (DSC) measurements were performed on porcine skin, which had been impregnated with KC and PH. Both showed a lowering ( approximately 5-6 degrees C) in the lipid phase transition temperature that occurs around 75 degrees C in porcine skin.