Cyproterone acetate-loaded nanostructured lipid carriers: effect of particle size on skin penetration and follicular targeting

Cyproterone acetate (CPA) is used to treat various skin disorders such as acne, hirsutism, and alopecia. Due to the limited skin penetration of CPA, nanostructured lipid carriers (NLCs) with different size ranges were considered in this study in order to enhance skin penetration and to target hair follicles. Drug loading, drug release and morphological assessment were evaluated for each targeted size (100, 300, and 600 nm). Ex vivo skin penetration was also investigated using Franz diffusion cells. Finally, in vivo follicular targeting was evaluated using rhodamine B-loaded micro and nanoparticles. Results revealed that 60-85% of drug was slowly released from lipid nanoparticles within 72 h. CPA-NLC with average diameter of 600 nm had better penetration and deposition in dermis-epidermis layer, also CPA-NLC 100 and 300 nm significantly increased drug penetration in dermis-epidermis in comparison to free CPA. Follicular targeting results revealed that NLC 300 nm had the best accumulation capacity in hair follicles. CPA-NLC with average diameter of 300 nm could be a promising topical novel drug delivery system for specific targeting of hair follicles and sebaceous glands to treat androgenic skin disorders such as acne, hirsutism, and alopecia.