Physical stability and antioxidant activity assay of a nanoemulsion gel formulation containing tocotrienol

Objective: Tocotrienols have an antioxidant potential higher than that of tocopherols. Nanoemulsion gel can deliver tocotrienols into the skin to prevent skin damage caused by free radicals and improve the stability of the dosage form. The present study aimed to determine the physical stability and antioxidant activity of a nanoemulsion gel formulation containing tocotrienol. Methods: The tocotrienol nanoemulsion was made using tocotrienols, oleic acid, Tween 80, 96% ethanol, and propylene glycol. The gel base was made using a carbomer and triethanolamine. A physical stability test was conducted at three different temperatures, namely, low temperature (4±2°C), room temperature (27±2°C), and high temperature (40±2°C). The antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl method for determining inhibitory concentration (IC₅₀) values. Results: Formula 1 demonstrated the best physical stability, with a pH of 6.2. The droplet size of the tocotrienol nanoemulsion gel was 596 nm, with a zeta potential value of −27.1 nm. The IC₅₀ of the tocotrienol nanoemulsion gel was 6252.14 ppm. Conclusion: The nanoemulsion gel formulation retained antioxidant activity and was physically stable for 8 weeks.