Development and evaluation of finasteride niosomes targeting to hair follicles for the management of androgenic alopecia

Finasteride, a selective Type II 5α-reductase inhibitor, has been approved as an oral drug for the treatment and prevention of androgenetic alopecia (AGA). The daily administration of finasteride by oral route may lead to various undesirable systemic side effects. In the present study, finasteride niosomes (FIN-NIS) as a dermal topical delivery system were developed evaluated in vitro/in vivo in an attempt to overcome the limitations of the oral administration of finasteride, enhance the retention of finasteride into hair follicles, and cause fewer adverse effects. FIN-NIS were prepared by ethanol injection method and characterized for particle size, entrapment efficiency (EE), in vitro release and in vitro skin retention. Testosterone-induced AGA mice model was used to evaluate the therapeutic effect of FIN-NIS. The results show that the particle size of FIN-NIS was about 260 nm with a good loading capacity, and the EE was greater than 90%. FIN-NIS had the sustained-release effect to some extent. Compared with the hydroethanolic solution of finasteride (FIN-hydroethanol) and finasteride suspension (FIN-suspension), FIN-NIS showed higher drug concentration in the excised rat skin, especially in the hair follicle area. The drug accumulation of FIN-NIS in the hair follicles was 20 times higher than that of FIN-hydroalcohol. In addition, FIN-NIS was more effective to promote hair regeneration in AGA mice than FIN-suspension, and the effectiveness of FIN-NIS even exceeded that of minoxidil. In conclusion, FIN-NIS could become a promising dermal topical delivery system for enhancing the performance of finasteride for the management of AGA and avoiding the possible risk of systemic side effects associated with oral administration.