Lipid extraction and transport of hydrophilic solutes through porcine epidermis

The purpose of this study was to investigate the effect of delipidization o f the stratum corneum (SQ on the in vitro percutaneous absorption of hydrop hilic solutes (i.e. water, urea, and inulin). Fourier transform infrared (F T-IR) spectroscopy was employed to study the extent of delipidization of po rcine SC due to chloroform:methanol (2:1) (C:M (2:1)) treatments for variou s time periods. In vitro percutaneous absorption of [H-3] water, [C-14] ure a, and [H-3] inulin were studied through C:M (2:1) treated epidermis in Fra nz diffusion cells. There was a greater decrease in peak areas of the asymm etric and symmetric C-H stretching absorbances (i.e. increase in lipid extr action) with increasing exposure times of the SC with C:M (2:1). After 40-m in treatment, asymmetric and symmetric C-H stretching peak area showed a de crease of 75.9 and 89.9%, respectively, The permeability coefficient of wat er, urea, and inulin increased with increasing lipid extraction. Enhancemen t in the permeability coefficient, through 40 min C:M (2:1) treated epiderm is in comparison to the control, for water, urea, and inulin was 48.72, 215 .65, and 3.90, respectively. Log (permeability coefficient) and log (mol. w t.) for test solutes and leuprolide acetate were found to be inversely rela ted (R-2 = 0.9974). In conclusion, this study implies that penetration enha ncers that are safe and extract the SC lipids can be selected in order to e nhance the percutaneous absorption of polar solutes through the skin. (C) 2 001 Elsevier Science BN. All rights reserved.