氨甲喋呤(MTX)脂质体的制备及其稳定性

本文探讨了提高MTX脂质体包裹率、影响它对热稳定性的因素,并自行设计了简便、迅速、重现性好的测定MTX脂质体的方法。结果表明:采用二次乳化蒸发法制备MTX脂质体,在控制乳化温度及有机相比例的条件下,可获得50%左右较高的包裹率。另外提示,脂质体分散溶媒的离子强度和脂质体中胆固醇的含量是影响MTX脂质体对热稳定性的重要因素。以选用50mM的磷酸盐缓冲液为分散溶媒和PC/CHOL/SA的脂质体组成,则100℃加热30分钟灭菌,所包MTX可滞留90%。且灭菌前后的脂质体经电镜观察形态无明显变化。     

氨甲喋呤(MTX)脂质体的制备及其稳定性

本文探讨了提高MTX脂质体包裹率、影响它对热稳定性的因素,并自行设计了简便、迅速、重现性好的测定MTX脂质体的方法。结果表明:采用二次乳化蒸发法制备MTX脂质体,在控制乳化温度及有机相比例的条件下,可获得50％左右较高的包裹率。另外提示,脂质体分散溶媒的离子强度和脂质体中胆固醇的含量是影响MTX脂质体对热稳定性的重要因素。以选用50mM的磷酸盐缓冲液为分散溶媒和PC/CHOL/SA的脂质体组成,则100℃加热30分钟灭菌,所包MTX可滞留90％。且灭菌前后的脂质体经电镜观察形态无明显变化。     

三尖杉酯碱脂质体的制剂研究

本文探讨三尖杉酯碱脂质体的较佳制备方法。表明用转相蒸发法(REV)制备时影响三尖杉酯碱脂质体包裹率的因素与大多数水溶性药物脂质体的影响因素相同。提出并经实验证实,以稠厚型脂质体贮存可减少内包三尖杉酯碱的渗漏。实验还表明脂质体100℃30分钟灭菌和10℃以下贮存五个月,制品的结构、粒度和包裹率均无明显改变,溶血试验合格。但在40℃加速实验1至3个月制品产生溶血,此溶血与卵磷脂的氧化有明显相关性。     

超临界二氧化碳法制备紫杉醇脂质体

目的介绍制备紫杉醇脂质体的新方法。方法采用超临界二氧化碳沉析技术制备紫杉醇脂质体。结果通过试验确定了最佳反应条件,即超临界压强为20 MPa,温度45℃,时间30 min,膜材配比(卵磷脂∶胆固醇)为3∶1,原药与膜材的质量比为1∶20,乙醇的质量分数为20%。在此条件下所制脂质体的包封率为76.18%。结论用此方法制备的脂质体包封率高,因此这是一种较好的脂质体制备方法。     

天麻素脂质体的研制

目的 研究天麻素脂质体的制备及包封率。方法 以逆相旋蒸法和超声法,采用卵磷脂和胆固醇二种膜材包裹天麻素,以Sephadex G50微型色谱柱分离脂质体,用高效液相色谱法测定包封率,色谱条件为:ULTRASP-ERE(TM)C18反相柱(4.6mm×25cm),流动相为甲醇-水(1:9),流速0.8ml/min,检测波长220nm。结果 以逆相旋蒸法,取卵磷脂与胆固醇摩尔比1:1制备的脂质体包封率最高,为(30.22±0.98)％。结论 天麻素制成脂质体的工艺稳定,包封率较高,条件易掌握,为提高天麻素生物利用度提供一种可能的新剂型。     

脂质体前体制剂研究进展

目的：脂质体前体的制备解决了脂质体分散系的物理不稳定性：如药物的渗漏、粒子的聚集以及磷脂在液态下的氧化、水解,为脂质体在临床上的应用提供了一个行之有效的方法,它使脂质体以固态形式贮存,只是在临用前加入分散介质即可再分散形成脂质体。方法：对近年来国内外脂质体前体的研究情况做文献检索,介绍了各种制备方法及影响新脂质体粒径和药物包裹率的因素。结果：通过适当的方法及选择合适的支持剂,可以制备出稳定性好、包裹率高的脂质体前体。结论：对脂质体前体的进一步研究有一定的意义     

酸敏脂质体的制备及其生物学活性

目的　对不同方法制备酸敏脂质体进行包封率测定及形态学观察 ,探讨酸敏脂质体包裹反义寡核苷酸的生物学效应。方法　测定四种不同方法制备包裹1 2 5I IL 8脂质体的包封率 ;在超高倍显微分析仪下观察形态结构。用包裹细胞磷脂酶A2 (cPLA2 )反义寡核苷酸的酸敏脂质体转染U937细胞 ,提取细胞RNA ,采用反转录 聚合酶链反应 (RT PCR) ;免疫印迹 (Westernblot)法检测cPLA2 蛋白的表达。结果　反相蒸发法与钙融合法联合制备的酸敏脂质体具有良好地包封率和形态结构 ,经酸敏脂质体包裹cPLA2 反义寡脱氧核苷酸可明显抑制cPLA2基因及蛋白的表达。结论　制备所得的酸敏脂质体可良好的发挥其生物学效应     

脂质体载体材料卵磷脂的制备及质量标准研究

目的：制备脂质体载体材料卵磷脂。方法：以新鲜鸡蛋为原料提取并制备了卵磷脂,并对卵磷脂的纯度,含量,氧化程度以及质量标准进行考察。结果：试验制备的卵磷脂为色谱均一的物质,含量高于98％,其氧化程度低,各项质量指标均符合美国药典规定。结论：结果表明,试验制得的卵磷脂可作为制备脂质体的载体材料。     

脂质体的胃肠道吸收Ⅱ.体内实验

本文目的是探索药物经脂质体包裹后对大鼠体内吸收的影响.用薄膜法制备双硬脂酰磷脂酰胆硷/胆固醇和卵磷脂/胆固醇多层脂质体,用逆相蒸发法制备双硬脂酰磷脂酰胆硷/胆固醇大单层脂质体.测定游离的和脂质体包裹的PEG-4000、氢化可的松和水杨酸的排泄曲线.游离的或脂质体包裹的PEG-4000口服给药后,尿液中无放射性检出,表明脂质体包裹不能促进标记物吸收.口服游离氢化可的松或脂质体后,2天内可从尿中回收约15%的放射性,其中大部分是在前24h内出现.所用脂质体类型(多层或大单层)和其类脂的组成并不影响排泄形式.脂质体包裹对口服后氢化可的松的吸收程度和速度均无影响.水杨酸的研究是将标记物包入在胃肠道中最稳定的一种脂质体(双硬脂     

间硝基二苯胺的薄层扫描定量分析

间硝基二苯胺经薄层层析后,用单波长外标两点法进行薄层扫描,不用显色直接定量,测定迅速、准确。测定四批样品,均得到较为满意的结果。     

Hydrophilic gels containing chlorophyllin-loaded liposomes: development and stability evaluation

The aim of this study was to develop and characterize hydrophilic gels containing chlorophyllin(CHL)-loaded liposomes as well as to evaluate their stability. Two different CHL-loaded liposome dispersions using non-hydrogenated and hydrogenated soybean lecithin were prepared, characterized for their particle size, polydispersity index and trapping efficiency and incorporated in Carbopol 940 NF hydrogel. The gels obtained were analyzed for flow properties, pH values and CHL content. The control liposome-free gel was obtained by incorporating the CHL solution in the hydrogel. The stability of the gels was evaluated in terms of rheological properties, pH values and CHL content during 6 months' storage at 20 +/- 2 degrees C. Suitable gel formulations for topical use were obtained revealing shear-thinning plastic flow behaviour without significant thixotropy during the whole period of examination. High yield values of the samples during the whole period indicated a long-term stability of the gel formulations. The gel formulations expressed a mild acid value acceptable for topical preparations. After 6 months' storage the CHL content was highest in the gel containing non-hydrogenated lecithin liposomes, followed by the gel containing hydrogenated lecithin liposomes and liposome-free gel, indicating that the encapsulation of CHL in liposomes led to a greater stability of CHL.     

正交试验优选盐酸川芎嗪脂质体的制备工艺

目的:优选盐酸川芎嗪脂质体的制备工艺。方法:以乙醚注入法制备川芎嗪脂质体,采用正交试验,以包封率为指标,以药物与大豆卵磷脂用量比、PBS缓冲液的pH值、胆固醇与大豆卵磷脂用量比、乙醚与PBS缓冲液用量比为考察因素,优选制备工艺。结果:最佳工艺条件为药物:大豆卵磷脂为1:12,PBS缓冲液pH为7.5,胆固醇:大豆卵磷脂为1:2,乙醚:PBS缓冲液为1:2。结论:该制备工艺可行、稳定、重现性好,可为工业化生产提供理论依据。     

醋酸泼尼松龙醇质体的制备及其药剂学性质考察

目的:制备醋酸泼尼松龙醇质体并考察其药剂学性质。方法:采用乙醇注入法制备醇质体。以包封率为指标,以处方中药物与大豆磷脂质量比(A)、胆固醇与大豆磷脂质量比(B)、无水乙醇占处方总量的百分比(C)为考察因素进行正交设计优化处方;考察优化后处方所制醇质体的形态、粒径、Zeta电位、包封率、稳定性等,差示量热分析法考察其热力学特性。结果:最佳处方为平均A包1:封20率,B为1(:766、.C793±0%0.2;9以)%此,处贮方藏制30备d的稳醇定质性体较外好形。圆差整示光量滑热,分平析均法粒结径果为(表2明78,.醋5±酸4泼6.7尼)松nm龙,Z以et无a电定位形为状(态-包31封.6于±醇0.0质4)体m中V,。结论:醋酸泼尼松龙醇质体制备工艺简单,优化处方所制制剂药剂学性质符合要求。     

Encapsulation efficiency of water-soluble and insoluble drugs in liposomes prepared by the microencapsulation vesicle method

The microencapsulation vesicle (MCV) method is a liposome preparation technique that reproducibly produces liposomes with homogeneous particle sizes with a high encapsulation efficiency. Liposomes encapsulating water-soluble drugs, lipophilic drugs and an amphiphilic drug were prepared by the MCV method and the encapsulation efficiency of the drugs was examined. Three kinds of egg yolk lecithin with different iodine values, i.e., purified egg yolk lecithin (PEL), partially hydrogenated purified egg yolk lecithin (R-20) and completely hydrogenated purified egg yolk lecithin (R-5), were used for membrane materials in order to explore the possible effects of membrane rigidity or surface area on the encapsulation efficiency of the drug. Water-soluble 5-fluorouracil showed 12-15% encapsulation efficiency, which was higher than those reported in the literature (less than 10%). With the MCV method, theoretically the initial drug-containing water phase was always separated from the dispersion medium by the lecithin-containing oil phase, which was advantageous to maintaining a higher encapsulation efficiency of the water-soluble drug. The encapsulation efficiency of lipophilic ibuprofen and flurbiprofen was around 90%. As for ketoprofen and liposomes were not formed when using hydrogenated egg yolk lecithin R-5, while the encapsulation efficiency using PEL or R-20 was around 80%. Amphiphilic amitriptyline hydrochloride resulted in a slightly higher encapsulation efficiency when dissolved in the water than the chloroform. Among the three kinds of lecithin, the most unsaturated PEL tended to show a higher encapsulation efficiency, probably due to differences in the packing geometry of the hydrophobic carbon chains in the membrane bilayer. The encapsulation efficiency of these drugs strongly correlated to the logP(octanol/water) and also tended to correlate to the logP(chloroform/water) for the order of the logP(chloroform/water) was almost the same as the order of the logP(octanol/water) in the drugs examined. As far as the results of this study, the logP(octanol/water) was considered to be a better indicator of the encapsulation efficiency of a drug in the MCV method.     

去氢骆驼蓬碱脂质体制备工艺优化及抗肝癌活性

目的 制备去氢骆驼蓬碱脂质体并对其制备工艺进行优化，评价脂质体的相关表征及对肝癌细胞的毒性。方法 用薄膜水化法制备去氢骆驼蓬碱脂质体。以包封率作为评价指标，以大豆卵磷脂和药物的质量比、大豆卵磷脂与胆固醇的质量比和超声时间作为评价因素对脂质体包封率的影响。并对脂质体的粒径、Zeta电位、外观和稳定性进行评价。CCK-8法对比去氢骆驼蓬碱和去氢骆驼蓬碱脂质体的抗肝癌细胞增殖活性。结果 最优制备工艺：大豆卵磷脂和药物的质量比为11.4：1，大豆卵磷脂与胆固醇的质量比为4.4：1，超声时间为33 min。在此条件下制备的脂质体的包封率为81.88%，粒径为143.65 nm，Zeta电位为-12.68 mV，低温环境稳定性良好，具有缓释效应。去氢骆驼蓬碱脂质体的抗肝癌细胞增殖活性大于裸药。结论 所制得的去氢骆驼蓬碱脂质体包封率和稳定性均符合标准。将去氢骆驼蓬碱制备成为脂质体能提高其抗肝癌细胞增殖活性。     

甲氨喋呤(MTX)多相脂质体的包封率测定与渗漏研究

本文参照文献确立了一种快速、准确、简便、适合于多相脂质体包封率测定法——葡聚糖凝胶微型柱—荧光法。测得结果表明,葡聚糖凝胶微型柱对于脂质体内外的MTX具有良好的分离效果,MTX多相脂质体的包封率为22%。并研究了MTX的渗漏,结果表明只能由脂质体内相向外渗漏,而不被脂质体摄取。     

A novel method to prepare liposomes containing amikacin.

This work describes a novel method to prepare liposomal amikacin composed of soyabean lecithin and cholesterol; these were also prepared using two other methods (cast film method and proliposome method). Encapsulation efficiency was evaluated. Liposomes prepared by the new method, which combines the method of preparing proliposomes with freeze-drying, had the highest encapsulation efficiency. The influence of drug to lipid ratio on the encapsulation efficiency was investigated. The in vitro efflux of amikacin from liposomes with different lecithin: cholesterol ratios was also investigated.     

Deformable liposomes for dermal administration of methotrexate

Deformable liposomes were prepared to investigate the effectiveness of dermal administration of methotrexate (MTX). The phospholipids used to prepare the liposomes were soybean lecithin (PC) or hydrogenated lecithin (HPC) and dipotassium glycyrrhizinate (KG) as surfactant. The lipid/KG ratio (w/w) was 2:1 and 4:1. Liposomes size, entrapment efficiency and MTX release through dialysis membrane were determined and the interaction between MTX and liposomes was investigated using differential scanning calorimetry. The MTX amount permeated through pig skin were three- to four-fold higher using liposomes containing KG compared to those from water solution or normal liposomes. No significant differences were observed between PC-KG liposomes and HPC-KG liposomes. At the end of the skin permeation assay using deformable liposomes, up to 50% of the administered dose was found in the skin. This capability depends on the self-regulating carrier deformability. These results suggest that liposomes containing KG may be of value for the topical administration of MTX in the treatment of psoriasis.     

Encapsulation of naturally occurring flavonoids into liposomes: physicochemical properties and biological activity against human cancer cell lines

Liposomes consisting of egg phosphatidylcholine were prepared by a thin-film hydration method followed by sonication and were used to investigate the percentage encapsulation of four flavonoids (quercetin, rutin, isoscutellarein and isoscutellarein diglycoside). The lipid recovery and the flavonoid-to-lipid molar ratio were measured using high-performance thin-layer chromatography/flame ionization detection and UV-vis spectroscopy. Differential scanning calorimetry was used to study the effect of the flavonoids on the phase transition temperature and on the enthalpy of the main phase transition of dipalmitoylphosphatidylcholine bilayers, and their ability to influence the membrane fluidity. The final liposomal formulation incorporating flavonoids, as well as free flavonoids, were tested for their activity against human cancer cell lines using the sulforhodamine B assay. The results showed that the encapsulation efficiency varied from 95% (0.21 flavonoid-to-lipid molar ratio) to 37.5% (0.09 flavonoid-to-lipid molar ratio) for isoscutellarein and its glycoside, respectively. The differential scanning calorimetry data showed close thermal and dynamic effects depending on the structure of the flavonoids, and suggest that there is a relationship between flavonoid molecular structure and the interaction with model membranes. Liposomal isoscutellarein showed improved growth inhibiting activity against all cell lines tested in comparison with that of its free form, which was inactive (>100 microM).