In-vitro digestion of curcumin loaded chitosan-coated liposomes.

Liposomes are considered a major route for encapsulation of hydrophilic and hydrophobic molecules. Chitosan coated liposomes could represent an alternative way as a carrier for delivery of drugs in human body. In this study the preparation and applicability of chitosan-coated liposomes containing curcumin as well as curcumin loaded anionic liposomes were evaluated. The applicability of the carriers was tested by means of an in-vitro digestion procedure allowing for measurement of the bioaccessibility of ingested curcumin. Values of diameter, polydispersity index and surface charge for curcumin loaded anionic liposomes obtained through dynamic light scattering and ζ-potential measurements were 129nm, 0.095 and -49mV, respectively. After chitosan-coating, diameter and polydispersity index remain unvaried while the surface charge gets positive. Slightly higher curcumin concentrations were found after the mouth and the stomach digestion phases when curcumin was loaded in anionic liposomes. On the contrary, after the intestinal phase, a higher percentage of curcumin was found when chitosan-coated liposomes were used as carrier, both in the raw digesta and in the bile salt micellar phase. It was shown that the presence of a positively charged surface allows a better absorption of curcumin in the small intestine phase, which increases the overall curcumin bioavailability. The mechanism behind these results can be understood from the composition of the different environments generated by the digestive fluids that differently interact with anionic or cationic surfaces.