Minoxidil Nanosuspension-Loaded Dissolved Microneedles for Hair Regrowth

Minoxidil (MIN) is used topically to treat alopecia. However, its low absorption limits its use, warranting a new strategy to enhance its delivery into skin layers. The objective of this study was to evaluate the dermal delivery of MIN by utilizing dissolved microneedles (MNs) loaded with MIN nanosuspension (MIN-NS) for hair regrowth. MIN-NS was prepared by the solvent-antisolvent precipitation technique. The particle size of MIN-NS was 226.7 ± 9.3 nm with a polydispersity index of 0.29 ± 0.17 and a zeta potential of −29.97 ± 1.23 mV. An optimized formulation of MIN-NS was selected, freeze-dried, and loaded into MNs fabricated with sodium carboxymethyl cellulose (Na CMC) polymeric solutions (MIN-NS-loaded MNs). MNs were evaluated for morphology, dissolution rate, skin insertion, drug content, mechanical properties, ex vivo permeation, in vivo, and stability studies. MNs, prepared with 14