Extemporaneous Topical Minoxidil Solutions for the Treatment of Androgenetic Alopecia- Stability Studies and Incorporation Tests of Active Pharmaceutical Ingredients in Aloplus Total Base.

Abstract

Minoxidil is one of the most employed active pharmaceutical ingredients for the  treatment of androgenetic alopecia. The authors propose a new method for production of minoxidil lotions using Aloplus Total. The latter is a propylene glycol-free liquid base in which the presence of hydroxypropyl-ß-cyclodextrin and ethanol allows the solubilization of high drug amounts. Minoxidil intrinsic solubility in the base was determined, and a comprehensive chemical and physical stability study was conducted on 8% w/w minoxidil lotions. Incorporation tests of different active pharmaceutical ingredients that can be combined to 5% w/w minoxidil were also carried out. The analyses showed that minoxidil intrinsic solubility in the new base was 85.93 mg/mL ± 4.17 mg/mL (8.64% w/w ± 0.42% w/w) at 25°C, and the topical lotions were found to be physically and chemically stable for more than 180 days when stored at 25°C or 40°C. Incorporation tests of several active pharmaceutical ingredients also were successful, indicating that Aloplus Total is a liquid vehicle also useful for the preparation of minoxidil-based topical lotions for a synergistic treatment of androgenetic alopecia.