琥珀酸胆固醇酯作为脂质体膜稳定剂的研究及其在制备柴胡皂苷-D脂质体中的应用

Cholesteryl hemisuccinate as liposomal membrane stabilizer and its use in the preparation of saikosaponin-D liposomes

目的研究琥珀酸胆固醇酯(CHEMS)对二棕榈酰磷脂酰胆碱(DPPC)脂质体的膜稳定作用以及作用机制;以 CHEMS 和 DPPC 为膜材制备柴胡皂苷-D(SSD)脂质体,考察其包封率和溶血性。方法差示扫描量热法(DSC)和荧光释放实验考察 CHEMS 的膜稳定作用,傅立叶红外(FT-IR)研究 CHEMS 与 DPPC 膜的作用机制,沉降实验研究 CHEMS 与 SSD 相互作用,溶血实验考察了以 CHEMS 为膜材包裹 SSD 脂质体的溶血性。结果 CHEMS 在膜稳定性上优于胆固醇(CHOL),CHEMS 与 DPPC 的极性端头同时有氢键和静电作用;CHEMS 与 SSD 不会形成不溶性复合物(INCOM),用 DPPC 和 CHEMS 为膜材制备了稳定的 SSD 包裹的脂质体,其溶血性大大降低。结论 CHEMS对 DPPC 膜的稳定作用大于 CHOL,并可取代 CHOL 作为制备胆同醇依赖性的溶血性皂苷脂质体的膜稳定剂。

Aim To study the membrane stabilization effect and mechanism of cholesteryl hemisuccinate(CHEMS)on dipalmitoylphosphatidylcholine(DPPC)liposomes:Saikosaponin-D(SSD) liposomes were prepared by using CHEMS as a membrane stabilizer and its encapsulation efficiency and hemolytic activity were evaluated.Methods Differential scanning calorimetry(DSC)and ealcein release were used to study membrane stabilization effect of CHEMS on DPPC membrane,Fourier transform infrared spectroscopy(FT-IR)was used to study the interacting mechanism of CHEMS with DPPC,sedimentation experiment was done to study the interaction of CHEMS with SSD and hemolytic study was used to evaluate the hemolytic activity of SSD-liposomes with CHEMS as membrane stabilizer.Results DSC analysis showed that CHEMS and cholesterol(CHOL)could all decrease the T_m value slightly and the △H value markedly.CHEMS was more effective than CHOL in decreasing the △H value of DPPC membrane.It suggested that CHEMS was more effective in increasing DPPC membrane stability.It was also proved by calcein release study carried out both in PBS and 30% plasma.The findings by FT-IR suggested that CHEMS has both hydrogen bond and electrostatic interaction with the polar head of DPPC.CHEMS did not form insoluble complex(INCOM)with SSD by sedimentation experiment.Stable SSD-liposomes were prepared using DPPC and CHEMS and decreased effectively the hemolytic activity of SSD,SSD-liposomes may be given intravenously at a concentration of 15 μg·mL^(-1),while free SSD was forbidden to be given intravenously.Conclusion CHEMS was more effective than CHOL in increasing DPPC membrane stability,and it could be of great use in the preparation of cholesterol-dependent hemolytic saponins- liposomes.The hemolytic activity of SSD-liposomes was greatly reduced,allowing a possible concentration of 15 μg·mL^(-1)to be intravenously administered.