Effect of Lipid Composition on In Vitro Release and Skin Deposition of Curcumin Encapsulated Liposomes

Liposomal encapsulation improves numerous physiochemical and biological properties of curcumin. The aim of this work was to impart slow release and skin delivery of curcumin via liposomal encapsulation. Liposomes were made using egg yolk phosphatidylcholine as the staple lipid while incorporating polysorbate 80 and stearylamine to prepare hybrid liposomes and positively charged liposomes, respectively. Negatively charged liposomes exhibited the highest encapsulation efficiencies (87.8 +/- 4.3%) and loading capacities (3.4 +/- 0.2%). The sizes of all formulations were about 250 nm, while stearylamine increased the polydispersity index. Positively charged liposomes showed lower degradation temperatures than negatively charged liposomes by 10-15 degrees C, attributable to the presence of stearylamine. The melting temperatures of positively charged liposomes (40-50 degrees C) were much higher than those of negatively charged liposomes (14-15 degrees C), which may have affected release and skin deposition behavior of liposomes. The positively charged liposomes exhibited the slowest release of curcumin in phosphate buffered saline (pH 6.8) and the release profiles of all liposomal formulations conformed to the Gompertz model. The negatively charged liposomes facilitated the highest skin deposition of curcumin as revealed by studies conducted using excised pig ear skin. Concisely, positively and negatively charged liposomes were optimal for slow release and skin deposition of curcumin, respectively.