Chitosan nanoparticles for targeting and sustaining minoxidil sulphate delivery to hair follicles

This work developed minoxidil sulphate-loaded chitosan nanoparticles (MXS-NP) for targeted delivery to hair follicles, which could sustain drug release and improve the topical treatment of alopecia. Chitosan nanoparticles were obtained using low-molecular weight chitosan and tripolyphosphate as crosslink agent. MXS-NP presented a monomodal distribution with hydrodynamic diameter of 235.5 +/- 99.9 nm (PDI of 0.31 +/- 0.01) and positive zeta potential (+38.6 +/- 6.0 mV). SEM analysis confirmed nanoparticles average size and spherical shape. A drug loading efficiency of 73.0 +/- 0.3% was obtained with polymer:drug ratio of 1:1 (w/w). Drug release through cellulose acetate membranes from MXS-NP was sustained in about 5 times in comparison to the diffusion rate of MXS from the solution (188.9 +/- 6.0 mu g/cm(2)/h and 35.4 +/- 1.8 mu g/cm(2)/h). Drug permeation studies through the skin in vitro, followed by selective recovery of MXS from the hair follicles, showed that MXS-NP application resulted in a two-fold MXS increase into hair follicles after 6 h in comparison to the control solution (5.9 +/- 0.6 mu g/cm(2) and 2.9 +/- 0.8 mu g/cm(2)). MXS-loading in nanoparticles appears as a promising and easy strategy to target and sustain drug delivery to hair follicles, which may improve the topical treatment of alopecia. (C) 2015 Elsevier B.V. All rights reserved.