Effect of high-pressure homogenization and stabilizers on the physicochemical properties of curcumin-loaded glycerol monooleate/chitosan nanostructures

Aim: The objective of this study was to investigate the influence of the high-pressure homogenization (HPH) process and stabilizers on the physicochemical properties of glycerol monooleate (GMO)/chitosan nanostructures using curcumin as a model hydrophobic drug. Materials & methods: The oil-in-water nanoemulsion of the GMO/chitosan system was prepared by sonication and HPH technioues using two different stabilizers (polyvinyl alcohol [PVA] and poloxamer 407). The particle size (PS), c-potential (ZP) and physical stability of the nanoemulsion were investigated. These nanoemulsions were lyophilized and characterized for PS, ZP, surface morphology, moisture content and physical form of the drug in the nanostructures. The in vitro release and the uptake of curcumin in Caco-2 cells were evaluated using an ultra-performance liquid chromatography method. Results: Three cycles of HPH produced a 50-65% reduction in the PS of the nanoemulsion. A change in stabilizer, from PVA to poloxamer, did not affect the PS, physical stability, moisture content or the physical form of the drug in the formulation. However, there was a significant change in the ZP, surface morphology, in vitro release rate and cellular uptake from the two formulations. Conclusion: The process of HPH effectively reduces the PS of the GMO/chitosan nanoemulsions loaded with the hydrophobic drug. The type of stabilizer used affects several physicochemical properties of the GMO/chitosan nanostructures. Compared with PVA, poloxamer 407 is a more effective stabilizer for stabilizing the GMO/chitosan system containing a hydrophobic drug nanoemulsion at low concentrations.