Development, Optimisation, and Biological Evaluation of Herbal Nano-Emulsion Gel Incorporating Centella asiatica, Curcuma longa, and Aloe vera Extracts for Accelerated Wound Healing

Wound healing represents a complex, multi-phase biological process involving haemostasis, inflammation, proliferation, and tissue remodelling, the efficiency of which is critically dependent on local microenvironmental conditions of moisture, microbial burden, oxidative stress, and growth factor availability. Traditional Indian medicinal plants — Centella asiatica (gotu kola), Curcuma longa (turmeric), and Aloe vera — possess extensively documented wound healing activities through complementary pharmacological mechanisms: triterpenoids of C. asiatica stimulate collagen synthesis and re-epithelialisation; curcumin from C. longa modulates NF-κB signalling to reduce chronic inflammatory mediator burden; and polysaccharides and acemannan of A. vera accelerate granulation tissue formation and provide moisture retention.This study develops and optimises an oil-in-water herbal nano-emulsion gel incorporating standardised ethanolic extracts of all three plants using Box-Behnken Response Surface Methodology (RSM) to maximise globule size uniformity, zeta potential, drug release rate, and spreadability. The optimised formulation (FO: 15% herbal extract complex, 8% coconut oil, 5% Tween 80, 2% PEG 400, 1.5% Carbopol 940) exhibits mean globule size 187.3 ± 12.4 nm, PDI 0.214, zeta potential −32.7 ± 2.1 mV, and pH 6.4. In vitro drug release across cellulose acetate membrane reaches 91.4% at 24 hours following anomalous (non-Fickian) transport kinetics (n=0.63). In vivo wound closure in a Wistar rat excision model demonstrates 97.6% wound closure by day 14 — significantly superior to framycetin sulfate standard (94.1%), plain herbal gel (88.4%), and untreated control (68.7%). Antimicrobial activity against S. aureus (ZOI 24.3 mm), E. coli (21.8 mm), P. aeruginosa (19.4 mm), and MRSA (22.1 mm) confirms multifunctional wound management efficacy.