Topical delivery of caffeine from some commercial formulations

Permeation of caffeine through human skin and artificial membranes (mounted in modified Franz type diffusion cells) was evaluated, either from saturat ed solutions or from commercially available topical formulations (all conta ining 3% caffeine). Data interpretation of the caffeine diffusion through h uman skin does not implicate transfer through pores despite caffeine being a relatively polar molecule. No correlation was found between transfer thou gh the synthetic membranes (cellulose acetate impregnated with isopropyl my ristate and silicone rubber soaked in isopropyl myristate) and that observe d through skin. The synthetic membranes can be used for assessing product p erformance in quality assurance but will give little indication of its perf ormance in vivo. The study investigated the percutaneous permeation of caff eine through human skin in order to obtain a mechanistic interpretation of its route of permeation. Synthetic membranes were also examined to determin e if they could be used as models for human skin. Different commercial form ulations investigated to determine the significance of enhancement strategi es. (C) 1999 Elsevier Science B.V. All rights reserved.