Preparation of wheat germ oil loaded solid lipid nanoparticles for topical use

Solid lipid nanoparticles loaded with wheat germ oil (WGO-SLN) were prepared by two different methods: double emulsification and hot homogenization, and with four different formulas. The samples with the lower concentration of lipid and surfactant were excluded from further testing because they were unstable. According to particle size in all tested products, 50% of the particles measured less than 300nm. This indicated that the particles that are in the 1μm size range in all four samples are more likely to be nanoparticle aggregates. The smallest mean particle size with the lowest polydispersity index was for the hot homogenization method. According to surface morphology test, which was done by TEM, both methods using higher concentration of lipid and surfactant presented uniform circular particles, whereas the particles in the lower concentration samples in both methods were not as clear. The results from the entrapment efficiency test indicated that the formulas with higher concentration of surfactant gave significantly higher percentage of entrapment of the oil, 77.36 ± 11.64 % for double emulsification method and 69.56 ± 5.81 % for the hot homogenization method. Whereas the lower concentrations formulas gave lower percentage of entrapment, 20.46 ± 4.43 % for the double emulsification method and 26.73 ± 4.43 % for the hot homogenization method. According to the stability test, the sample prepared with the double emulsification method and the lower concentration of lipid and surfactant was the least stable, and the sample prepared with the hot homogenization method and the higher concentration of lipid and surfactant was the most stable.