Transdermal Delivery of Minoxidil with Block Copolymer Nanoparticles

The study investigated the transdermal delivery of minoxidil using self-assembled nanoparticles of two different sizes, 40 nm and 130 nm, made from poly(ε-caprolactone)-block-poly(ethyleneglycol). It was found that in hairy guinea pig skin, the smaller 40-nm nanoparticles enhanced minoxidil permeation by 1.5-fold in the epidermal layer and 1.7-fold in the receptor solution compared to the 130-nm nanoparticles. This size-dependent permeation was not observed in hairless guinea pig skin. The study concluded that the main pathway for these nanoparticles was through shunt routes like hair follicles, and smaller nanoparticles promoted better permeation.