FORMULATION AND EVALUATION OF A pH-RESPONSIVE CHITOSAN BASED POLYHERBAL NANOGEL CONTAINING CLITORIA TERNATEA, PUNICA GRANATUM PEEL AND CENTELLA ASIATICA FOR WOUND HEALING

Wound healing is a dynamic biological process involving hemostasis, inflammation, proliferation and remodeling. The development of intelligent topical delivery systems has attracted interest because the wound microenvironment can change during healing and infection. The present research work was undertaken to formulate and evaluate a pH-responsive chitosan based polyherbal nanogel containing Clitoria ternatea flower, Punica granatum peel and Centella asiatica extracts for wound-healing applications. Chitosan was selected as the principal polymeric matrix, while methacrylic acid was incorporated to provide pH-responsive behaviour, with N,N′-methylenebis(acrylamide) and ammonium persulfate used in the cross linking/polymerization system. Four formulations (F1–F4) were prepared with different polymer, initiator, monomer and cross-linking levels and evaluated for organoleptic properties, pH, viscosity, spreadability, homogeneity, grittiness, gel strength, swelling behaviour and colour response. The formulations were translucent to opaque, homogeneous and free from grittiness. The pH ranged from 5.62 to 5.95, viscosity from 3370 to 6240 cps, spreadability from 6.5 to 7.4 cm, swelling behaviour from 186.3% to 243.6%, and gel strength from 66.8 to 105.4 s. A noticeable colour response was observed at different pH values, supporting the intended colorimetric pH-responsive property. Among the formulations, F3 showed a favourable overall balance of pH, viscosity, spreadability, swelling behaviour, gel strength and homogeneity. The findings support further investigation of the formulation as a multifunctional topical wound-care system; however, additional physicochemical characterization, stability, safety, biological and clinical studies are necessary before therapeutic use.