Preparation of Asialofetuin-Labeled Liposomes with Encapsulated Human Interferon-γ and Their Uptake by Isolated Rat Hepatocytes

The selective delivery of human recombinant interferon (IFN)- to isolated rat hepatocytes was studied with asialofetuin (AF)-labeled liposomes. AF-liposomes containing buffer solution were initially prepared by the detergent removal method, and IFN- was subsequently encapsulated by the freeze-thawing method without loss of activity. Virtually no free [³²P]IFN- was internalized into isolated rat hepatocytes, whereas AF-liposomes containing [³²P]IFN- were taken up to a significant degree. Liposomal binding to the hepatocytes (estimated at 4°C) was one-fifth of the uptake (estimated at 37°C). Since the uptake was inhibited by the addition of free AF, AF-liposomes may be taken up by the action of galactose-binding protein on the hepatocytic cell surface. The liposome preparation method reported in this paper provides a useful means for the encapsulation of unstable macromolecules into AF-liposomes. AF-liposomes were found effectively to carry IFN- into hepatocytes in vitro.     

Pharmacokinetic and Pharmacological Profiles of Free and Liposomal Recombinant Human Erythropoietin After Intravenous and Subcutaneous Administrations in Rats

Purpose. Recombinant human erythropoietin (Epo) is used frequently through intravenous (i.v.) and subcutaneous (s.c.) administration for the clinical treatment of the last stage of renal anemia. We encapsulated Epo in liposomes to develop an alternative administration route. The purpose of our study was to evaluate the pharmacokinetics and the pharmacological effects of liposomal Epo in comparison with the Epo after i.v. and s.c. administration to rats. Methods. Epo was encapsulated in liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and soybean-derived sterol mixture (SS) prepared by the reversed-phase evaporation vesicle method. After filtration through a 0.1 m polycarbonate membrane, liposomes were gel filtered (Epo/liposomes). Results. Epo/liposomes showed higher pharmacological activity than Epo/liposomes before gel filtration after i.v. administration to rats. Non-encapsulated Epo lost its activity, whereas encapsulated Epo in liposomes retained it. The pharmacological effects of Epo/liposomes were greater than those of Epo after i.v. administration. Epo/liposomes afforded 3–9 times higher AUC, lower clearance and lower steady-state volume of distribution than Epo after both i.v. and s.c. administrations. Epo/liposomes had an improved pharmacokinetic profile compared with Epo. S.c. administration of Epo/liposomes at 7 h may penetrate primarily (40% of dose) through the blood as a liposome and partly (7% of dose) in lymph. Conclusions. Epo/liposomes may reduce the frequency of injections required for a certain reticulocyte effect in comparison to Epo. The lower clearance of Epo/liposomes may increase the plasma concentrations of Epo, which increases the efficacy.     

LHRHa靶向紫杉醇脂质体的制备及体外抗肿瘤作用

目的:制备促黄体激素释放激素类似物(Luteinizing hormone-releasing hormone analogues,LHRHa)靶向紫杉醇脂质体(Paclitaxel liposomes,PTX-Lipo),研究其在体外增强紫杉醇(Paclitaxel,PTX)对卵巢癌A2780/DDP细胞的抑制作用。方法:采用薄膜超声法制备PTX-Lipo与LHRHa靶向紫杉醇脂质体(LHRHa-Paclitaxel liposomes,LHRHa-PTX-Lipo),用透射电镜考察脂质体形态;高效液相色谱法测定2种PTX-Lipo的包封率;激光共聚焦法通过卵巢癌A2780/DDP细胞对4-氟-7-硝基-2,1,3-苯并氧杂恶二唑荧光素的摄取检测来反映细胞对NBD-Lipo与NBD-LHRHa-Lipo的摄取情况;MTT法及细胞克隆形成实验检测LHRHa-PTX-Lipo体外对卵巢癌细胞的生长抑制情况。结果:制备LHRHa-PTX-Lipo的平均粒径123.4 nm,包封率在90%以上;A2780/DDP细胞对NBD-LHRHa-Lipo组的荧光摄取明显高于NBD-Lipo组;LHRHa-PTX-Lipo对A2780/DDP细胞的生长及克隆形成抑制明显高于PTX组及PTX-Lipo组(P<0.05)。结论:采用薄膜超声法制备的LHRHa-PTX-Lipo可使药物在靶部位聚集,增强药物对卵巢癌细胞的抑制作用。     

9-硝基喜树碱脂质体的制备及大鼠肺部给药药动学

目的制备9-硝基喜树碱(9-NC)脂质体,研究其经大鼠肺部给药后的体内药动学行为。方法以薄膜分散-超声法制备9-NC脂质体,用粒度测定仪测定粒径,采用离心法分离脂质体和未包封药物并用HPLC法测定包封率,通过肺部滴注给药考察脂质体在大鼠体内的药动学行为,用液液萃取法处理血浆样品,反相HPLC法测定不同时间点大鼠血浆中的药物浓度。结果9-NC脂质体平均粒径为167.6nm,包封率为(91.51±2.63)%(n=3)。9-NC脂质体和溶液剂经肺部给药后,体内药物动力学参数分别为t1/2(3.88±0.90)h和(0.72±0.07)h,AUC0→t(215.88±16.47)μg·h·L-1和(95.29±6.04)μg·h·L-1,MRT(3.72±1.65)h和(1.10±0.08)h。结论与溶液剂相比,9-NC脂质体肺部给药后具有一定的缓释作用。     

An Experimental Study on Homoharringtonine Liposome and Glaucoma Filtration Surgery

Purpose: To observe the inhibitory action of homoharringtonine liposome during the healing process of wounds in the filtering sitesMethods: posterior sclerectomies were performed in 14 rabbits. Postoperatively one eye of each rabbit received subconjunctival injections of HH liposome and fellow eye received saline injection in a randomized masked fashion.Results; Fourteen days after operation the IOP of experimental eyes reduced significantly (P < 0.01) as compared with the controlled eyes, and the number of remaining filtering blebs increased noticeably (P< 0.05). Pathohistological examination revealed that the number of fibroblasts per square micron in the filtering sites and the thickness of the scars in the center of the filtering sites of the experimental eyes were less than those of the controlled eyes. No serious ocular toxic and side effects were found.Conclusion : This experiment suggests that homoharringtonine liposome can markedly inhibit the scar formation of filtering sites after glaucoma fi     

藻酸双酯钠脂质体的制备及粒度分布的测定

目的制备藻酸双酯钠脂质体并对其聚结稳定性进行评价。方法采用蛋黄卵磷脂为包封材料,逆向蒸发法制备藻酸双酯钠脂质体,将藻酸双酯钠脂质体与空白脂质体对照,分别测定了它们经37℃,40h温育前后的粒度分布,计算平均粒径。结果在n(PC)∶n(CHOL)=1∶1的条件下,藻酸双酯钠脂质体的平均粒径为4.24μm,温育后,藻酸双酯钠脂质体的平均粒径只增加了0.26μm,而空白脂质体的平均粒径增加了1.35μm。结论藻酸双酯钠载于脂质体上,提高了脂质体的聚结稳定性。     

冻干水化(DRV)型脂质体作为免疫佐剂可行性的研究

目的 对ＤＲＶ型脂质体作为免疫佐剂的可行性及稳定性进行研究。方法 改良的ＤＲＶ型脂质体的制备;并用ＥＬＩＳＡ、ＭＴＴ法、皮肤迟发型过敏反应（ＤＴＨ）及整体的抑瘤试验,ＴＢＡ法、碘值、氧化指数和气质联用分析法进行鉴定。结果 （１）ＤＲＶ型脂质体能增强小鼠对抗原（粘液糖蛋白、核心多肽及其基因肽）的体液免疫和细胞免疫;疫苗免疫后Ｃ５７小鼠有杀瘤作用（对照组７９％成瘤,疫苗组为４０％）。（２）ＤＲＶ型脂质     

注射用柴胡挥发油脂质体制备工艺研究

目的 :探讨将柴胡挥发油制成注射用脂质体的制备工艺可行性。方法 :通过研究柴胡挥发油脂质体的处方组成、挥发油包封率、冻干可行性以及二者的指纹图谱变化。结果 :柴胡挥发油的包封率为 81.9%。经冷冻干燥后 ,脂质体中被包封挥发油的保留率为 88.6 %。结论 :将柴胡挥发油制备成注射用脂质体在制备工艺上是可行的。