Isotretinoin-Delonix polymeric nanoparticles: Potentials for skin follicular targeting in acne treatment.

In acne management, oral isotretinoin (IST) is associated with various untoward systemic effects, while its topical formulation has irritation side effects. Delonix (DLX) is a natural galactomannan derived from Delonix regia seed that can fabricate nanoparticles for topical skin delivery. This study aims to develop IST-DLX nanoparticles and assess their prospects for acne treatment. Fluorescent-DLX nanoparticles (made with a lipophilic BODIPY dye) or IST-DLX nanoparticles were prepared and characterized. BODIPY-DLX nanoparticles' skin distribution and IST-DLX nanoparticles' in-vitro targeting were assessed in pig ear skin, inflammatory modulation was assessed in AMJ-2 macrophage cells, while skin penetration and irritation were assessed in Wistar rats. IST-DLX nanoparticles had ≈230 nm, negative zeta potential, and ≈30% encapsulation efficiency. Confocal showed BODIPY in DLX nanoparticles accumulated in hair follicles as compared to BODIPY solution. IST-DLX nanoparticles released ≈37% IST over 48 h and increased IST 3-fold in hair follicles compared to IST solution. IST-DLX nanoparticles suppressed IL-6 expression in cells and reduced photo-irritation in Wistar rats compared to IST solution. In conclusion, IST-DLX nanoparticles may target and deliver adequate IST to skin layers associated with acne, avoid systemic penetration, modulate inflammatory pathogenic acne stage and prevent IST topical photo-irritation.