橄榄苦苷脂质体包封率测定方法探讨

目的:采用微柱滤过法测定橄榄苦苷脂质体的包封率。方法:用20 ml的注射器装填葡聚糖凝胶,取40 μl的样品加至柱头后,先用2倍柱体积的纯化水冲柱,再用50%的乙醇溶液洗柱,收集洗脱液,测定吸光度值,根据洗脱曲线计算脂质体中游离橄榄苦苷的含量,推算包封率。结果:在橄榄苦苷出峰处,脂质体对测定无干扰;橄榄苦苷在1~16 μg·ml^-1范围内,吸光度与浓度线性关系良好(r²=0.999 6);1,1.5及2 mg·ml^-1橄榄苦苷与空白脂质体混合后的过柱回收率分别为(110.00±2.35)%,(109.75±2.63)%及(97.97±1.82)%;同一批橄榄苦苷脂质体重复测定6次包封率的RSD为1.76%。结论:本方法准确、简便,适于橄榄苦苷脂质体包封率的测定。

Investigation on encapsulation efficiency for oleuropean liposome

OBJECTIVE To determine encapsulation efficiency of oleuropean liposome by using method of microcolumn filtration.METHODS Injector of 20 ml was used and filled with sephadex G50. Sample of 40 μl was added to column head, followed by the washing with distilled water of a volume equivalent to two times of column volume. Then the column was cleaned by 50% ethanol. Eluent was collected in tubes and absorbance was measured. Content of free oleuropean in liposome was calculated according to elution curve. Encapsulation efficiency was obtained through concentration of free oleuropean.RESULTS Liposome did not interfere with assay of oleuropean at its retention time. Absorbance increased as concentration elevated in a linear mode when oleuropean was in range of 1 to 16 μg·ml^-1 (r²=0.999 6). Column recovery of oleuropean mixed with blank liposome at concentration of 1, 1.5, and 2 mg·ml^-1, was (110.00±2.35)%, (109.75±2.63)% and (97.97±1.82)%, respectively. RSD of encapsulation efficiencies, determined six times for the same batch of oleuropean liposome, was 1.76%.CONCLUSION This method is accurate, simple, and applicable to assay of encapsulation efficiency of oleuropean liposome.