Lipased-catalyzed synthesis of palm-based wax esters, J. Oleo Sci. 53(10). (2004), pp. 471-477.[Gunawan et al., 2004], [Mat Radzi et al., 2006] and [Basri et al., 2007]) as the lipophilic phase was studied with nonionic surfactants and water. The palm-based nanoemulsions were prepared using high-energy emulsification to supply the emulsion system with sufficient amount of energy as to form the dispersed surfactant-encapsulated nanodroplets. The effects of amount of surfactant and different pressures, cycles, stirring rate and duration were studied to produce the nanodroplets. Stability of the palm-based nanoemulsions was also investigated with regards to their Ostwald ripening rate. The results showed that the type and composition of surfactant were important for the formation and stability of the nanoemulsions. Lipophilic surfactant, SPAN® 20 gave the smallest droplets size range (78-120 ± 2 nm) as compared to hydrophilic surfactant, Tween® 60 (105-180 ± nm). Introducing high pressure and cycle reduced the size tremendously after the pre-mixing. Stirring rate and duration also affected the nanodroplets formation. Increasing processing temperature led to the deformation of the nanodroplets which is the key finding in the searching of emulsification route that produce the most stable system. The investigation on the formation and stability of palm-based nanoemulsions is very important in the preparation for poorly water-soluble lipophilic actives/drugs for cosmetic and medicinal formulations. Moreover, its water-like fluidic rheological behavior is excellent as a vehicle for topical cosmetics and pharmaceuticals.

Palm oil esters (POEs), which are newly synthetic liquid wax esters with HLB value of 9.34, were proposed as a lipophilic phase for formation of nanoemulsion. Phase diagrams show domination of two-phase regions at all emulsification temperatures ranging from 30 to 80C. Spontaneous and temperature-induced emulsification, high-shear and high pressure homogenization were utilized to form nanoemulsion. However, only high pressure homogenization successfully produced droplets sizes in the nano range. Thus, it was used to optimize the stability properties of POEs nanoemulsion. The manipulation of processing temperatures during the formation of emulsions could be used in lowering the droplets size of the emulsion.