Relative uptake of minoxidil into appendages and stratum corneum and permeation through human skin in vitro

This study examined the uptake of minoxidil, a hair growth promoting agent, into appendages, stratum corneum, and through human skin, under the influence of different vehicles. The study found that deposition of minoxidil into appendages, stratum corneum, and skin penetration into receptor fluid were similar in magnitude. Transport by the appendageal route is likely to be a key determinant of hair growth promotion by minoxidil. The study also showed that ethanol-containing formulations caused significantly greater minoxidil retention in stratum corneum and appendages, compared to the formulation lacking ethanol. A significant increase in minoxidil receptor penetration occurred with the propylene glycol-rich formulation after 12 hours.