工艺参数对层状液晶乳液结构的影响

讨论了由聚氧乙烯醚失水山梨醇脂肪酸酯、失水山梨醇脂肪酸酯、直链脂肪醇和挥发性物质组成的层状液晶乳液的制备过程中乳化时原料的加入顺序、乳化时间、冷却时搅拌速度及冷却时间对乳液的形态(脂质体结构,洋葱结构),特别是对乳液颗粒的粒径及粒径分布的影响。结果表明:乳化过程的时间对粒径的分布无明显影响;将水加入到含表面活性剂的油相中有利于形成完整结构的液晶乳液;冷却过程中的搅拌速度及搅拌时间对粒径的影响最大,为了得到较大颗粒为主的粒径分布,较佳冷却条件是搅拌速率在1 500 r/min、冷却60 min;慢速冷却有利于形成层间距较大的层状液晶,快速冷却易形成层间距略小的层状液晶。     

抗坏血酸类脂质体纳米药物载体合成

以自制月桂酸甘油酯为原料,选择超声乳化法制备了抗坏血酸类脂质体。又分别用生物显微镜、透射电子显微镜、扫描电子显微镜观察抗坏血酸类脂质体的显微形态结构和表面结构,说明甘油二酯能够形成纳米药物载体,为类脂质体的合成提供了一种原料。     

Antioxidant activity of green teas in different lipid systems

Different commercial green teas from Japan, China, and India, were compared in different lipid systems. Green teas were active antioxidants in bulk corn oil oxidized at 50°C but were prooxidant in the corresponding oil-in-water emulsions. Green teas also were active antioxidants in soybean lecithin liposomes oxidized at 37°C in the presence of cupric acetate as catalyst. At 50°C, however, three of the samples of green tea were active antioxidants in the absence of copper catalyst, and two samples showed prooxidant activity in the presence of copper catalyst. The marked variation in activity among green tea samples may be due partly to differences in their relative partition between phases in different lipid systems. The improved antioxidant activity observed for green teas in lecithin liposomes compared to corn oil emulsions can be explained by the greater affinity of the polar tea catechin gallates for the polar surface of the lecithin bilayers, thus affording better protection against oxidation. Liposomes may thus be appropriate lipid models to evaluate antioxidants for foods containing phospholipids.     

Inhibition of lipid peroxidation and nonlipid oxidative damage by carnosine

The antioxidant effects of carnosine on lipids and nonlipids, including liposomes, carbohydrates, and proteins, were investigated. Carnosine exhibited a remarkable antioxidant effect in liposome and deoxyribose model systems. Carnosine at high amounts (50 mg/mL) was effective in protecting protein against oxidation. The correlation coefficients between reducing ability and the inhibition of liposome, albumin, and deoxyribose oxidation were r=0.92, 0.83, and 0.41, respectively. Carnosine exhibited metal-binding ability and scavenging ability for hydroxyl radicals generated by photolysis of H₂O₂ with UV light. The correlation coefficients between hydroxyl radical scavenging and the inhibitory effect on deoxyribose, liposome, and albumin oxidative damage were r=0.97, 0.60, and 0.29, respectively. These properties may explain how carnosine protects lipids and non-lipids against oxidative damage.     

脂质体载药系统经皮给药的研究进展

脂质体是一类具有特殊性质的磷脂，近几年已开始被广泛用作多种药物的载体。药物经皮给药系统是药剂学中的一新兴的领域，通过脂质体包埋技术制备的各种经皮给药系统同样在我国的制药和化妆品行业得到广泛应用。通过对脂质体的组成及一般特性、脂质体载药系统经皮给药的药剂学促透机制和最新的基础实验和应用研究进展的综合分析后显示，脂质体包裹技术在国内相关领域中的应用将具广阔的前景。     

磁性脂质体的制备及应用研究进展

综述了纳米磁性粒子和磁性脂质体的制备方法,同时简要介绍了磁性脂质体在磁性分离、靶向药物、热疗、组织工程和造影剂等领域的应用进展.     

Effects of surface charge of low molecular weight heparin-modified cationic liposomes on drug efficacy and toxicity

Cationic liposome is a potential nanocarrier to deliver drugs to solid tumor with proven efficiency in targeting tumor tissues. However, the major limitation is their charge-related instability and blood toxicity via intravenous injection. In order to overcome these problems and to maintain tumor targeting potency, we modified the cationic liposomes with low molecular weight heparin (LMWH) to obtain series of liposomes with different surface charges. Both in vitro and in vivo studies including serum stability, blood hemolysis, cellular uptake, cytotoxicity and in vivo biodistribution were evaluated. The results indicated the cationic liposome with surface charge of 5?mV (denoted as LLip-C) had the similar stability in serum and mild hemocytolysis compared with that of anionic liposome (LLip-D), but better cellular uptake owing to electrostatic interaction between cationic liposomes and cell membranes. Furthermore, we prepared curcumin-loaded liposomes to investigate the therapy efficiency. The intracellular distribution of curcumin-loaded LLip-C (Curcumin-LLip-C) was inclined to locate in cytoplasm and nuclei than curcumin-loaded LLip-D (Curcumin-LLip-D). In vitro cytotoxicity of Curcumin-LLip-C also exhibited higher inhibition of tumor cells than that of Curcumin-LLip-D. These results certified that a slightly positive surface charge of nanocarriers could achieve the balance between well antitumor efficiency and mild adverse effects.     

仙人掌SOD脂质体的制备研究

采用逆相蒸发法制备仙人掌SOD脂质体，最佳工艺为：卵磷脂与胆固醇的质量比为2：1，乙醚与SOD酶液的比为3：1，经超声乳化和旋转蒸发可制得包封率为56％的脂质体，包封后的SOD在胃蛋白酶的作用及高温下，比游离的SOD稳定。     

冻干技术在注射用盐酸吉西他滨脂质体中的应用

为研究影响冻干过程的主要影响因素,考察冻干技术在注射用盐酸吉西他滨脂质体中的应用,以外观性状、水分、复溶、粒径、含量、有关物质为指标,对冻干工艺中参数进行优化.优化后的冻干工艺为:2.5％甘露醇为冻干保护剂;快速预冻,温度为-50℃,时间为4h;真空度为15Pa;升华干燥的温度为-38℃,时间为25h;解析干燥的温度为30℃,时间为6h.通过优化冻干工艺参数,所得的盐酸吉西他滨脂质体冻干制品外观平整、质地疏松,加水后分散均匀,含量及有关物质均符合规定,多次重复实验结果基本稳定.     

新型有机-无机杂化陶瓷型脂质体“Cerasome”的研究与应用

Cerasome是20世纪90年代末制备出来的一种新型有机-无机杂化的陶瓷型脂质体,与传统的脂质体相比,它的表面覆盖了一层硅酸盐网络结构,因而兼具有机和无机性质.无机硅酸盐的网络结构使它具有良好的形态稳定性,克服了传统脂质体在这方面存在的巨大缺陷.综述了形成Cerasome的前体化合物、Cerasome的制备及性质,对其在三维纳米杂化体构建、新型磁性杂化材料的制作、基因转染载体以及生物膜模拟等领域的研究进行了的评述,并对Cerasome未来的研究发展趋势进行了展望.