Enhanced intestinal absorption of curcumin in Caco-2 cell monolayer using mucoadhesive nanostructured lipid carriers

This study aimed to compare the intestinal permeation of curcumin-loaded polymer coated nanostructured lipid carriers (NLCs) and uncoated NLCs using the Caco-2 cell model. The uncoated NLCs were prepared using a warm microemulsion technique, while polymer-coated NLCs were prepared with the same method but were followed by coating particle surface with polyethylene glycol (PEG) 400 or polyvinyl alcohol (PVA). After lyophilization, all formulations possessed a mean size of <400 nm with a zeta potential of ∼-30 mV and a high entrapment efficacy up to 90%. All NLCs formulation showed significantly improvement in curcumin water solubility, more than 60-folds as compared to curcumin dispersion. In addition, they could protect curcumin from degradation in basic pH, 90% curcumin remaining after 6 h incubation in culture medium. In vitro permeation studies revealed that PEG-NLCs and PVA-NLCs provided significantly higher apparent permeation coefficient (P_app ) value than uncoated NLCs. Moreover, after 6 months storage at 4 °C in the absence of sunlight, the physical, and chemical stabilities of the lyophilized curcumin-loaded polymer coated NLCs and uncoated NLCs could be maintained, i.e., the mean particle size and the amount of curcumin showed no significant changes (p > 0.05) compared to those freshly prepared formulations. Considered overall, polymer coated NLCs are an important strategy to improve the oral bioavailability of curcumin. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 734-741, 2018.