Effect of β-sitosterol on the curcumin-loaded liposomes: Vesicle characteristics, physicochemical stability, in vitro release and bioavailability

In this work, the effect of β-sitosterol (Sito) on vesicle characteristics, physicochemical stability as well as the in vitro release and bioavailability of curcumin-loaded liposomes (Cur-LP) was studied. When 20–33 mol% of Sito was incorporated, encapsulation efficiency of curcumin was improved due to the high amount of liquid-ordered domains in membranes. At 50 mol% Sito a lower encapsulation efficiency was observed possibly due to membrane defects. The physical, thermal and photo stability of curcumin in liposomes were markedly improved with increasing the amount of Sito. First-order kinetics fitted best the curcumin release dynamics of Sito containing liposomes, clearly showing that sustained release improved with increasing amounts of Sito in liposomes. Simulated digestion studies suggested that Sito concentration of about 20–33 mol% improved the bioavailability of curcumin in liposomes. These study shows that Sito is an applicable and potential route in forming healthier cholesterol-free curcumin-loaded liposomes for functional supplements.