Preparation of curcumin nanoemulsions in virgin coconut oil (VCO)-Tween 80 system with wet-ball milling method

Curcumin is one of the most popular medicines due to its various pharmacological properties. Nonetheless, curcumin has low bioavailability, insoluble in water, and aggregates easily. This can be overcome by formulating curcumin into nanoemulsion. One of the methods to produce nanoemulsion is wet-ball milling. The aims of this study are, firstly, to determine the optimum milling time to produce curcumin nanoemulsion in the Virgin Coconut Oil (VCO)-Tween 80 system, and secondly to determine the curcumin loading capacity and efficiency of encapsulation. The optimum milling time is evaluated based on the particle size, polydispersity index, and nanoemulsion stability. Curcumin loading capacity and efficiency of encapsulation is analyzed based on the maximum mass of curcumin added in the system which still can maintain particle size in the range of nanoemulsion (under 1000 nm) and the amount of curcumin entrapped in the droplets. Curcumin nanoemulsion was made by the combination of 1 mg curcumin powder, 200 μl VCO as oil phase, 60 μl Tween 80 as surfactant, and 5 ml distilled water as the dispersion medium. Meanwhile, the milling time is varied at 1, 4, 8 and 24 hours. Particle size and polydispersity index are measured using Particle Size Analyzer using Dynamic Light Scattering technique while encapsulation efficiency is calculated based on the curcumin absorption using UV-Vis spectrophotometer. The results show that curcumin nanoemulsion system milled for 24 hours produce smallest particle size (160 nm), lowest polydispersity index (0.176), and stable during 30 days in the storage at room temperature (25 °C) and refrigerator temperature (4 °C). The maximum of curcumin that can be added in the nanoemulsion and produce particle size below 500 nm is 300 mg. Encapsulation efficiency obtained is 78.13 % of the total curcumin in the nanoemulsion system. In summary, the current work has demonstrated the successful incorporation of curcumin into oil in water (O/W) nanoemulsion particles with small particle size, low index polydispersity, good physical stability, and high encapsulation efficiency.