Characteristics and Hair Growth Efficacy of Water Dissolving Micro-needles Containing Minoxidil Regarding Length of Micro-needles

Abstract

Two types of polymeric micro-needles with 250 and 750 µm lengths were prepared by a micromolding process. The geometry of dissolving micro-needles with minoxidil was investigated and the mechanical property of polymer micro-needles was also evaluated. Water dissolving micro-needles containing minoxidil were successfully inserted into skin and delivered minoxidil to the skin layer after 30 min of insertion. The observed hair growth was less when the minoxidil treatment was not applied or used without the micro-needles than that the minoxidil was applied by micro-needles. Histologically, these hair follicles became bigger, and the hair papillae were totally encircled by the hair bulbs. In this feasibility test, we show the successful delivery of minoxidil, and effective treatment of hair loss can be possible by using dissolving micro-needles with minoxidil.Keywords: water dissolving polymer, micro-needle, microstructure, micromolding, hair growth.