NANOEMULSION FOR IMPROVED PERMEABILITY OF CENTELLA ASIATICA EXTRACT: FORMULATION, EX-VIVO AND IN-VIVO EVALUATION

Centella asiatica L. Urban (family: Umbelliferae) contains several active triterpenoids which have been reported to induce type I collagen which decreases substantially in photoaged skin. Centella asiatica extract is highly soluble in water but have low absorption into the skin. To overcome this, water in oil nanoemulsion loaded with Centella asiatica extract have been formulated, optimized and evaluated as the potential delivery system for treating photoaging. Nanoemulsions were formulated by the oil phase titration method and optimized by constructing pseudo-ternary phase diagrams. The prepared nanoemulsions were subjected to thermodynamic stability testing. Those that passed these tests were characterized for droplet size, polydispersity index, zeta potential and droplet morphology by Cryo-SEM. The prepared nanoemulsions were in nanometric range (optimized batch: 140.5 nm) with uniform size distribution (PDI: 0.086) and good physical stability (zeta potential: -33.9 mV). Topical permeation of Centella asiatica loaded nanoemulsion through porcine abdominal skin was estimated using the Franz diffusion cell. A significant increase in permeability parameters was observed in nanoemulsion formulations (P<0.05) as compared to an aqueous solution of Centella asiatica extract. Topical application of CA nanoemulsion loaded cream to rat hind limb significantly reduced the wrinkle formation on UV exposed skin. Histopathological studies of the skin samples further confirmed the antiphotoaging effects of the prepared nano-emulsion formulation.