Evaluation of the percutaneous absorption of promethazine hydrochloride, in vitro, using the human ex vivo skin model.

For several years, pharmacists have been using vehicles such as Pluronic lecithin organogel and Lipoderm for the delivery of medication, including promethazine, through the skin. This study evaluated the percutaneous absorption pharmacokinetics of promethazine hydrochloride 25 mg/g in Pluronic lecithin organogel and the commercial base Lipoderm,in vitro, in human ex vivo skin, using the finite dose technique and Franz Diffusion Cells. Due to the polar nature of promethazine hydrochloride, it was theorized that this drug would present a transdermal challenge for these two commonly utilized compounding bases. An amount of 5 mcL/cm squared of each formulation was applied to triplicate sections of skin from three different ex vivo skin donors. At 4, 8, 12, 24, 32, and 48 hours post-application, the reservoir solution in the Franz Cell was removed and analyzed. Lipoderm performed better than Pluronic lecithin organogel based on total absorption into the reservoir solution (2.86% +/- 0.79 vs. 1.73% +/-0.85) (P less than 0.2). Total permeation through and beyond the stratum corneum (epidermis, dermis, and reservoir solution) after 48 hours was significantly greater for Lipoderm than for Pluronic lecithin organogel (23.06% +/- 3.33 vs. 10.31% +/- 5.44), with the Student's t-test showing statistical significance (P less than 0.001). These data indicate that promethazine hydrochloride does penetrate into and through human ex vivo skin in vitro using Lipoderm and Pluronic lecithin organogel, with Lipoderm showing better results.