Temperature-responsive detachable microneedles integrated with minoxidil nanoparticle for effectively promoting hair regrowth

Androgenetic alopecia (AGA) is one of the most customary inducement of hair loss, and topical minoxidil (MXD) has been widely used to treat AGA, but the drug delivery rate is seriously limited by the poor solubility of MXD and traditional inefficient transdermal delivery methods. Microneedles (MNs) can directly puncture the skin for administration with improved drug delivery rate and weaker side effects. However, the common solid MN is easy to fall off, especially in hairy areas, which reduces the duration of drug action. To ensure robust attachment and prolong the drug efficacy, we designed minoxidil nanoparticle-loaded hyaluronic acid (HA) microneedles and integrated with a switchable temperature-responsive adhesion ring, which polished the solubility of MXD and made the MNs retained in the body for a longer time and improved clinical operability. In AGA model, the MXD NP-loaded MN system could promote the hair follicles transformation from telogen phase to anagen phase. Compared with the application of the traditional minoxidil solution, our MN system can achieve therapeutic effect with a lower dose and frequency, which reduced side effects and advanced user compliance. Therefore, this transdermal delivery system can possibly offer a promising strategy for treating alopecia and other dermatoses.