Polymeric Micelle Nanocarriers for the Cutaneous Delivery of Tacrolimus: A Targeted Approach for the Treatment of Psoriasis

The study aimed to improve the cutaneous delivery of tacrolimus (TAC) for psoriasis treatment by formulating TAC-loaded polymeric micelles using the biodegradable and biocompatible MPEG-dihexPLA diblock copolymer. The optimal 0.1% micelle formulation was stable for 7 months at 4 °C, with diameters ranging from 10 to 50 nm. Delivery experiments using human skin showed significantly greater TAC deposition with the micelle formulation compared to Protopic ointment (1.50 ± 0.59 vs. 0.47 ± 0.20 μg/cm²). The increased TAC levels were localized in the stratum corneum, viable epidermis, and upper dermis without deeper skin penetration or systemic absorption, suggesting reduced side effects. Confocal laser scanning microscopy confirmed micelle deposition in hair follicles and indicated that micelle release depended on the molecular properties of the cargo. The results demonstrated that MPEG-dihexPLA micelles are highly efficient for selective cutaneous TAC delivery and have potential for targeted hair follicle delivery.