Natural Sweetener Stevioside-Based Dissolving Microneedles Solubilize Minoxidil for the Treatment of Androgenic Alopecia

Abstract

Androgenetic alopecia (AGA) is a prevalent form of non-scarring hair loss. Standard treatments, which include minoxidil (MXD) tincture and foam, face challenges due to MXD's water insolubility and poor skin permeability. The result is extended treatment duration and reduced therapeutic effectiveness. This study utilized stevioside (STV), a natural sweetener derived from the Stevia plant, as a novel solubilizing excipient and microneedle (MN) material. A solid dispersion of STV with insoluble drugs is developed and molded into an MN patch. STV significantly increased MXD's solubility to 47 mg mL−1 in water, ≈18 fold higher than the control. STV solubilizes MXD by forming micelles in aqueous solution with a critical micelle concentration of 15 mg mL−1. In vitro skin permeation studies showed cumulative drug release of 85% and 18% skin retention for the MN patch, which indicated excellent drug absorption into the skin. Animal studies demonstrated that the MN patch significantly promoted hair growth. There is a significant increase in hair follicle transition to the growth phase, which resulted in 67.5% coverage of the treatment area by day 35. Collectively, the results highlight the potential of the STV MN delivery system for the treatment of AGA.