Effect of surfactants on percutaneous absorption of naproxen II: in vivo and in vitro correlations in rats.

The effect of surfactants on percutaneous absorption of naproxen was studied using rat in vivo models. The in vivo normalized relative absorption rates were in good agreement with the in vitro relative flux. An antipyretic model in the rat could not show relatively small increases in percutaneous absorption caused by the surfactants. Based on these results, it is apparent that reliance on the rat, using either in vitro or in vivo models, may lead to erroneous conclusions when considering the effect of surfactants on human percutaneous absorption of drugs such as naproxen.