Optimization of a liposomal delivery system for the highly antioxidant methanol extract of stem-bark of Schumacheria castaneifolia Vahl

The highly antioxidant methanol extract of stem-bar k of Schumacheria castaneifolia was studied for the effect of variation of the cholesterol content on the propert ies of liposomes. Liposomal formulations displayed colloidal dimensions and negative zeta-potentials; and the st ability varied with the lipid composition. The lipo somes consisting of 9:1 and 8:2 ratio of egg yolk phospha tidylcholine to cholesterol were optimal for the hi ghest encapsulation efficiency (86%) and loading capacity (8%) of the plant extract. The release properties of plant extract encapsulated liposomes depended on the lipi d composition. Liposomal plant extract exhibited sl ow release over 7 h with slower release in artificial sweat th an in phosphate buffered saline or deionized water. Interactions between phospholipids and cholesterol, and polyphen ols of the plant extract and phospholipids appear tthe properties of liposomes.