Terpenes Encapsulated Polycaprolactone Nanoparticles for Topical Delivery of Hydrocortisone: <i>In Vitro</i> Study and <i>In Vivo</i> Appraisal

This work aimed to develop and assess terpene encapsulated polycaprolactone (PCL) nanoparticles for topical delivery of hydrocortisone (HC). Formulations were designed to investigate the effect of terpene/PCL ratio and concentration of surfactant on physicochemical characteristics. Structural analyses were studied using differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy techniques. Ex vivo skin permeation and anti-inflammatory activity of HC were also appraised. Results showed that the physicochemical characteristics were particularly influenced by terpene/PCL ratio and concentration of surfactant. The selected formulation (F6) showed core-shell structure and good encapsulation of HC in less crystalline state. Higher skin flux (366.11 ± 32.8 µg/cm 2 /h) and permeability coefficient (17.57 ± 2.6 × 10 2 cm/h) of HC from gel based on F6 were observed when compared with crude drug gel. Anti-inflammatory activity of HC was significantly improved and showed sustained therapeutic action when using gel based on F6. Collectively, these findings suggest that terpene encapsulated PCL nanoparticles can potentially deliver HC through the skin.