Design, development and characterization of phosphatidylcholine liposomes to be used as carriers bioactive extracts

The aim of this work was to standardize the elaboration of phosphatidylcholine liposomes to be used as carriers of natural bioactive extracts. After characterization of the raw materials, diverse liposomes were elaborated from different purification-grade phosphatidylcholines (2 or 5 washes) extracted from soybean lecithin and different sonication procedures (120W-5min or 30W-2min). A control lecithin liposome was also studied. Once selected the most appropriate conditions, liposomes were loaded with bioactive products of different nature from agro-industrial waste or underutilized sources: sea fennel, pomegranate peel, crustacean bio-wastes or fish collagen. The lipid fractionation evidenced that the purification washes promoted the phosphatidylcholine concentration (95% of the total lipids) reducing free fatty acids and neutral lipids (90%). Besides, the phosphatidylcholine signal was 164 times greater than that for other phospholipid classes. The phosphatidylcholine concentration was higher (p≤0.05) in the five-washes sample, that explains the more accentuated reduction in free fatty acids and neutral lipids than in two-washes sample. These results were supported by the FTIR data. All liposomes presented high stability (< -30mV), being the liposome prepared from phosphatidylcholine with five-washes, and strong sonication (L5A) the smallest (87nm). The endothermic transition peaks and enthalpy changes shown by this liposome reflected its great phosphatidylcholine concentration and higher bilayer stability. The prevalence of small unilamellar vesicles was confirmed by transmission electronic microscopy. The different bioactive extracts added to L5A-liposome did not change the mean size or morphology, and provided good storage stability and high antioxidant properties.Peer reviewe