Evaluation of the pH effect of formulations on the skin permeability of drugs by biopartitioning micellar chromatography.

Dermal absorption of chemicals is an area of increasing interest for the pharmaceutical and cosmetic industries, as well as in dermal exposure and risk assessment processes. Biopartitioning micellar chromatography (BMC) is a mode of reversed phase micellar chromatography that has proved to be useful in the description and prediction of several pharmacological properties of xenobiotics including oral drug absorption, ocular and skin drug permeability. The present paper deals with the application of biopartitionig micellar chromatography to evaluate the pH effect on the skin permeability of twelve non-steroidal anti-inflammatory drugs and lidocaine. For this purpose the BMC retention of the whole set of compounds at several pHs between 3.5 and 8 was obtained. Using the BMC retention-permeability model previously reported, the permeability of the compounds at different pH values was estimated. The predicted permeability values at different pH values for ketoprofen, lidocaine, salicylic acid and ibuprofen agree with those experimental reported in literature for these compounds using excised human and rat skin.