顺磁性脂质体包封率测定方法的研究

Study on entrapment efficiency of paramagnetic liposomes

目的:建立Gd-DTPA顺磁性脂质体包封率的测定方法。方法:采用薄膜分散-高压均质法制备顺磁性(Gd-DTPA)脂质体。分别采用透析法、超速离心法、超滤离心法分离脂质体和游离药物,并用电感耦合等离子体-原子发射光谱法(ICP-AES)测定其中钆的含量,计算脂质体包封率。结果:ICP-AES法测定钆浓度在2～10mg·L-1范围内线性关系良好(r=0.9996);高、中、低3种浓度的日内和日间精密度试验的RSD均小于1%;消解方法的平均回收率(98.1%～100.3%)符合要求;3种包封率测定方法中超滤离心法测得的包封率最高,透析法测得的包封率最低。结论:超滤离心法结合ICP-AES法快捷、准确,适用于Gd-DTPA顺磁性脂质体包封率的测定。

Objective：To establish a method for determination of the entrapment efficiency of paramagnetic liposomes.Methods：The paramagnetic（Gd-DTPA） liposomes were prepared by thin film dispersion-high pressure homogenization.The liposomes and free drug were separated by dialysis,ultracentrifugation and ultrafiltration,then Gd concentration were determined by inductive coupled plasma-atomic emission spectrometry（ICP-AES）,and then the entrapment efficiency of the liposomes was calculated.Results：The calibration curve was linear（r=0.9996） with in the range of 2-10 mg·L-1 for gadolinium determined by ICP-AES.The RSDs of the intra-day and inter-day were less than 1%,and the recoveries of the digesting method were 98.1%-100.3%.Among the three methods,the entrapment efficiency determined by ultrafiltration was the highest,and the entrapment efficiency determined by dialysis was the lowest.Conclusion：The method of ultrafiltration with ICP-AES is rapid,accurate and reproducible.It is suitable for determining the entrapment efficiency of the paramagnetic liposomes.