‬‬‬‬‬‬‬‬Development and characterization of polymeric nanoparticle-based formulation of adapalene for topical acne therapy‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬.

The purpose of this study is to develop a new formulation of adapalene for the topical treatment of acne. We investigated applicability of polymeric nanocarriers based on tyrosine-derived nanospheres (TyroSpheres) for adapalene delivery. TyroSpheres effectively encapsulated adapalene and substantially enhanced its aqueous solubility, while decreasing the crystallinity of the drug in the formulation. Skin distribution of adapalene via TyroSphere formulation was evaluated ex vivo using human cadaver and porcine ear skin, and this was compared with the commercial adapalene formulation, Differin®. Sustained drug release across stratum corneum in 51 h was observed from TyroSpheres. Additionally, in vitro skin irritation studies demonstrated that encapsulation of adapalene in TyroSpheres significantly reduced the irritancy of the drug to monolayer HaCaTs and reconstituted human epidermis (EpiDerm™, MatTek Corp.). The results suggest that TyroSpheres provide a promising carrier system to deliver hydrophobic drugs to hair follicles and upper epidermis while minimizing skin irritation of the encapsulated drug.