固相萃取-荧光分光光度法快速测定脂质体包封率

Rapid determination of entrapment efficiency of liposomes by solid phase extraction-fluorospectrophotometry

以紫杉醇作为模型药物,旨在建立一种固相萃取-荧光分光光度法快速测定脂质体包封率的方法。分别采用水和75%甲醇对SampliQ C18固相萃取柱上的紫杉醇脂质体及其游离态进行洗脱分离,并在激发波长λex=244 nm、发射波长λem=311 nm条件下,利用荧光分光光度法测定游离紫杉醇的含量,从而间接计算紫杉醇脂质体的包封率。在本文建立的方法下,紫杉醇在0.006～0.078 mg/mL范围内线性关系良好(r=0.998),C18固相萃取柱对空白脂质体和游离紫杉醇的回收率均在97.5%以上。该方法测得自制紫杉醇脂质体包封率为50.8%(RAD=1.5%),与微柱离心法测得结果相比无显著性差异。实验结果表明,本方法可快速、简便地实现游离紫杉醇与其脂质体的分离测定,为脂质体的质量控制研究提供参考。

The objective of this study was to establish a method for the determination of the entrapment efficiency of liposomes by solid phase extraction-fiuorospectrophotometry. Paclitaxel was selected as the model drug. SampliQ C18 solid phase extraction columns were applied to separate free paclitaxel and its liposome using water and 75% methanol solution as elute solutions, respectively. A fluorospectrophotometries method （ λex=244 nm, λex=311 nm） was applied to determine the entrapment efficiency of paclitaxel liposome. Tile calibration curve was linear in the range of 0. 006-0. 078 mg/mL（ r = 0. 998）, and the recoveries of blank liposome and free pacli- taxel were all above 97.5%. The entrapment efficiency of paclitaxel liposome determined by this method was 50. 8% （ RAD = 1.5% ）, which has no significant difference from those results measured by mini-column centrifu- gation. Solid phase extraction-fluorospectrophotometry could be applied to determine the entrapment efficiency of paclitaxel liposome rapidly and accurately and could be used to control the quality of paclitaxel liposome.