595 In vitro evaluation of skin distribution and human dermal papilla cells proliferation for minoxidil 5% topical lotion hydrogel

Abstract

For decades, the treatment of reference for androgenetic alopecia has been the topical application of minoxidil 2% or 5%, which is commercially available as a solution and a foam. When compounded, minoxidil may be incorporated in variable strengths to a topical base in order to meet the individual needs of men. An alternative topical compounded formulation was developed to include minoxidil in a proprietary hydrogel that is alcohol-free to reduce the skin irritation, and does not require pH adjustment to facilitate the compounding process. In vitro studies were conducted to investigate the proliferation of human dermal papilla cells upon treatment with minoxidil 5% topical lotion hydrogel. Additional in vitro studies evaluated the distribution of minoxidil across the skin. The commercial product of reference was used as positive control. For the proliferation analysis, the bromodeoxyuridine staining assay identified the proliferating human dermal papilla cells upon 24 hours of exposure by minoxidil 5% (commercial product versus compounded formulation), using fluorescence detection. The proliferation effect of minoxidil was significant in both minoxidil commercial (RFU 181,446 ±38,171, p=0.021) and minoxidil compounded (RFU 183,109±24,416, p=0.006), when compared to the negative control (untreated cells). For the skin distribution, the Franz Skin Finite Dose Model evaluated the percutaneous absorption of minoxidil into the dermis and receptor medium using skin samples from two male Caucasian donors. Following a skin integrity test and 3 hours of diffusion, the minoxidil was extracted from the dermis layer and analyzed by UPLC. It was shown that the percutaneous absorption into the dermis and receptor medium was similar for the two minoxidil products. The in vitro performance of the minoxidil 5% topical lotion hydrogel was comparable to the commercial product of reference. As such, the easy to compound, alcohol-free formulation is a promising therapeutic alternative in androgenetic alopecia.