A thermoresponsive spray-based no-contact delivery system for burn and diabetic wound care

No-contact drug delivery to burn and diabetic wounds remains a major challenge despite advancements in surgical dressings and technology. To address this, a smart polymer-based system containing Asiatic acid and curcumin was selected for its complementary wound-healing properties. Curcumin offers anti-inflammatory and antimicrobial effects while Asiatic acid stimulates collagen synthesis and tissue regeneration. An in-vitro scratch assay using L929 mouse fibroblast cells confirmed a synergistic effect between Curcumin and Asiatic acid, with enhanced fibroblast migration and faster wound closure compared to individual actives. To enable a non-contact application, a thermosensitive gel spray (TSGS) formulation was developed. Nine formulations containing curcumin-hydroxypropyl-β-cyclodextrin (HP-β-CD) complex and Asiatic acid were prepared using varying concentrations of hydroxypropyl methylcellulose_ Methocel™ K100M (HPMC K100M) (20%, 25%, 30%) and Poloxamer 407(0.5%, 1%, 1.5%) concentrations. The optimised thermosensitive gel spray showed in-vitro release of 40-45% of both actives in 7 h vs. 20-30% from conventional gels and 70-90% of cumulative release at 24 h vs. 35-50% from standard formulations. It maintained stable gelation temperature and practical drying time at 5 ± 2 °C, 25 ± 2 °C/60% RH, and 40 ± 2 °C/75% RH, respectively. In-vivo studies in rats showed the optimised spray significantly promoted re-epithelialization and neovascularisation during the inflammatory phase, outperforming both silver sulfadiazine cream and conventional Asiatic acid-curcumin gel. The histopathology images also support the hypothesis.