Eugenol emulsions stabilized by a natural-derived nonionic palmitate surfactant/polyacrylic acid complex

Eugenol emulsions based on a palmitate surfactant were prepared. The palmitate surfactant was synthesized via a simple esterification reaction of poly(ethylene glycol) (M-n 10,000 g mol(-1)) and palmitic acid. Subsequently, the surfactant was combined with poly(acrylic acid) (PAA) to give intermolecular complexes that served as the emulsions' stabilising agents. Different ratios of PAA/surfactant complexes were used for the preparation of emulsions. Emulsions with a PAA/surfactant complex ratio of 1/3 gave long-term stable emulsions with hydrodynamic diameters ranging from 62 to 89 nm and narrow size distributions at a quite low emulsifier concentration. The latter emulsions loaded eugenol up to 85%. Furthermore, eugenol emulsions successfully encapsulated the poor-water soluble compound curcumin, increasing its solubility up to 6 times.

Automated summary

Stable eugenol emulsions were prepared by synthesizing palmitate surfactant and forming complexes with poly(acrylic acid), which led to successful encapsulation of eugenol up to 85% and improved solubility of the poor-water soluble compound curcumin up to 6 times.