Formulation and stability testing of nanoemulsion lotion containing centella asiatica extract

Objective: Centella asiatica (Pegagan) contains asiaticoside for treatment of striae patients by increasing the synthesis of collagen. Asiaticoside has a large hydrophilic molecule (959.12 g/mol), causing difficulty in penetration through the skin. Nanoemulsion has small droplet size so that the active substance can be delivered into the skin layer. This study aims to formulate and test the stability of nanoemulsion lotion containing pegagan extract. Methods: Nanoemulsion containing pegagan extract formulated in the form of lotion using High Pressure Homogenizer. Nanoemulsion lotion were then evaluated and tested for penetration in vitro. Result: The mean particle size of nanoemulsion was 19.88 ± 2.3 nm and nanoemulsion in lotion was 198.4 ± 11.52 nm; polydispersity index value 0.329 ± 0.065, and zeta potensial was -30.9 mV. Nanoemulsion lotion was stable against storage for 8 weeks at cold, room, and high temperature (4 ± 2°C, 28 ± 2°C, 40 ± 2°C). There were no change in physical properties and pH value of the nanoemultion lotion.The cumulative amount of the penetrated asiaticoside was 1558.65 ± 66.93 μg/cm² for nanoemulsion lotion and 1260.364 ± 71.42 μg/cm² for lotion only. Flux of nanoemulsion lotions and lotion were 2.1255 ± 0.31 μg/cm²/hr and 1.4506 ± 0.49 μg/cm²/hr, respectively. Conclusion: It can be concluded that nanoemulsion lotion stable in physical properties during storage and can penetrate more than the non nanoemulsion lotion.