Development of NLC-based Sunscreen Gel of Green Tea Extract and its In vitro Characterization

Background: Green tea extract is a hydrophilic antioxidant. The challenge associated with its cutaneous administration is its poor penetration. A system of solid-liquid lipids formulated in the form of a nanostructured lipid carrier (NLC), can improve the penetration. In addition, Vitamin E oil used as a liquid lipid will aid in skin hydration, reduce particle size, and enhance penetration. Objective: The objective of this study was to formulate the NLC-based sunscreen gel of green tea extract. Methods: Nanostructured lipid carriers (NLC) were prepared by melt emulsion ultrafiltration technique and were evaluated for particle size, zeta potential, polydispersity index (PDI), drug loading (DL), encapsulation efficacy (EE), and in vitro drug release. The optimised formula was incorporated into a suitable gel base and an in vitro sun protection factor (SPF) was determined. Beeswax and Vitamin E oil were chosen as solid and liquid lipids for NLC formulation. Results: The particle size, PDI, zeta potential, entrapment efficiency, and in vitro drug release of optimised formulation (NLC4) were found to be 139.4 nm, 0.236, -11.0 mV, 84.20%, and 85% respectively. The SPF value of green tea extract-NLC-loaded gel was found to be 20.035. Conclusion: The result of the current investigation depicted that lipid nanoparticles are suitable carriers for green tea extract to be delivered as sunscreen gel.