超滤-HPLC法测定盐酸拓扑替康脂质体包封率

Determination of entrapment efficiency of topotecan liposomes by ultrafiltration-HPLC

目的：对盐酸拓扑替康脂质体进行质量评价，测定盐酸拓扑替康脂质体的包封率。方法：采用超滤法分离脂质体与游离药物；采用HPLC测定药物含量，计算包封率。结果：超滤法能很好地将脂质体与游离药物分离，游离药物的平均回收率在96．9％～102．3％之间，超滤加样回收率在96．7％～101．6％之间，脂质体不能透过截留相对分子质量为50000的超滤膜。在所选色谱条件下，盐酸拓扑替康得到良好分离，辅料不干扰测定，盐酸拓扑替康在1．0～40．0mg·L^-1内线性关系良好（r=0．9998），日内和日间RSD均〈3．0％（n=5），加样回收率在98．5％～100．3％之间，RSD为1．4％。用此方法测定3份盐酸拓朴替康脂质体的包封率为92．41％～95．14％，RSD在1．26％～2．03％。结论：该方法可用于盐酸拓扑替康脂质体包封率的测定。

Objective：To determine the entrapment efficiency of topotecan hydrochloride liposomes. Methods：An ultrafihration was employed to separate the free drug from the liposomes. The content of topotecan hydrochloride was quantified by HPLC consisted of a Kromasil C,s column, a mobile phase of water-acetonitrile-trifluoroacetic acid （85 ： 20：0.1 ） with a flow rate of 0.8 mL· min^-1 and UV detection wavelength at 228 nm. Results： The free topotecan hydrochloride was well separated from the liposomes using uhrafihration membrane that blocks the penetration of a compound with molecular weight of 50 000 or above. The recovery rate of topotecan hydrochloride by uhrafihration and free topotecan was in a range of 96.7% - 101.6% and 96.9% - 102.3% , respectively. A calibrated linear curve of topotecan concentration was within 1.0 -40.0mg·L^-1（ r = 0. 999 8 ） , and RSD within day and between days was all less than 3.0% （ n = 5） , the recovery rate of topotecan with blank liposomes was in a range of 98.5% - 100.3% with RSD of 1.4% or below. The entrapment efficiency of three batches of topotecan hydrochloride liposomes was in a range of 92.41% - 95.14% ,with RSD of 1.26% -2.03% by uhrafiltration-HPLC. Conclusion ： The ultrafiltration-HPLC method may be used for the determination of entrapment efficiency of topotecan hydrochloride liposomes.