微柱离心法测定紫杉醇脂肪乳的包封率

目的：建立一种微柱离心方法测定紫杉醇脂肪乳包封率。方法：采用SephadexG-50微柱，分别以适量体积的水及乙醇为洗脱液分离脂肪乳中的包封药物和游离药物。通过考察洗脱过程中紫杉醇及脂肪乳中油相成分大豆油的含量（紫杉醇的含量测定采用HPLC法，大豆油的含量测定采用HPLC-ELSD法），并以外加法制备的包封不完全的紫杉醇脂肪乳的洗脱曲线确立包封药物和游离药物的分界点，确定了最终的洗脱方式及洗脱液用量：以1 mL水，共洗3次将脂肪乳中包封药物完全洗脱，以3 mL乙醇，共洗2次将脂肪中游离药物完全洗脱。并以方法的回收率和重复性，对方法进行了验证。最终以建立的方法测定了3批紫杉醇脂肪乳样品的包封率。结果：微柱离心法能有效实现紫杉醇脂肪乳中包封药物和游离药物的分离。方法的回收率为100.4%，RSD为0.60%（n=9）；重复性为99.4%，RSD为0.58%（n=5）。3批样品的包封率分别为99.2%、99.3%、99.5%。结论：该法操作简便，回收率高，重复性好，能区分不同包封情况的紫杉醇脂肪乳，测定结果准确可靠。

Objective: To establish a minicolumn centrifugation method for the determination of entrapment efficiency of paclitaxel lipid emulsion.Methods: The Sephadex G-50 minicolumn was employed to separate paclitaxel lipid emulsion and free drug with a moderate volume of water and ethanol as the eluents.By investigating the content of paclitaxel and soybean oil in lipid emulsion in the elution process(Paclitaxel content was determined by HPLC method and soybean oil content was determined by HPLC-ELSD method.) and establishing the boundary point of encapsulated drug and free drug according to elution curves of incomplete encapsulating emulation prepared with external additive, ultimate elution mode and eluents dosage were determined.The encapsulated drug was eluted for 3 times with 1 mL water and free drug was completely eluted for 2 times with 3 mL ethanol.The method was verified with the recovery and repeatability.Eventually, the entrapment efficiency of three batches of paclitaxel lipid emulsion was determined by the established method.Results: The method of minicolumn centrifugation could effectively separate the free drug from paclitaxel lipid emulsion.The column recovery was 100.4% and RSD was 0.60%(n=9).In repetitive experiments, average entrapment efficiency was 99.4% and RSD was 0.58%(n=5).The entrapment efficiencies of three batches of samples were respectively 99.2%, 99.3% and 99.5%.Conclusion: The method is technically simple with high recovery rate and good reproducibility.The method can distinguish different entrapment efficiency of paclitaxel lipid emulsion and the result is accurate and reliable.