Supercritical assisted production of Lutein-loaded Liposomes and Modelling of drug release

In this work, a lipophilic ophthalmic drug, lutein, has been entrapped in liposomes, using a supercritical assisted process. Effects of pressure, temperature, and drug to lipid ratio variation were studied on mean diameters and lutein encapsulation efficiency. Liposomes with diameters between 153 ± 38 and 267 ± 56 nm were produced, and lutein encapsulation efficiencies between 86.5 _ 0.4% and 97.8 ± 1.2% were obtained. A Scanning Electron Microscope confirmed spherical shape and mean dimensions of vesicles. The variation of temperature for the production of liposomes showed a significant impact on lutein retention time in the double lipidic layer. Lutein drug release from liposomes produced at 35 ºC ended in almost 4.5 days; whereas, liposomes produced at 40 ºC showed a faster lutein release in 3 days; then, vesicles obtained at 45 ºC released their lutein content in only 2 days. Drug release raw data were well-fitted using Weibull model (R-square up to 99%).