乳糖化-去甲斑蝥素磷脂复合物及其pH敏感型脂质体的制备

目的:合成乳糖化-去甲斑蝥素磷脂复合物,并制备其pH敏感型脂质体。方法:将乳糖化-去甲斑蝥素与磷脂聚合成药物磷脂复合物,并采用FT-IR、DSC和1H-NMR对其进行表征。逆向蒸发法制备药物磷脂复合物脂质体;利用羧甲基壳聚糖与脂质体表面的静电吸附作用,使羧甲基壳聚糖吸附在脂质体表面,制备乳糖化-去甲斑蝥素磷脂复合物pH敏感型脂质体;考察了药物与磷脂的复合率,磷脂复合物脂质体的包封率,粒径大小和分布,以及体外释药特性。结果:药物磷脂复合率为(97.2±2.01)%,磷脂复合物脂质体的平均包封率为(70.00±1.30)%,平均粒径为(47.18±4.16)nm,粒径跨距为(0.70±0.07),电镜显示其形态圆整,体外释药符合Weibull方程。结论:乳糖化-去甲斑蝥素磷脂复合率高,制成的pH敏感型脂质体性质稳定,且具有缓释特性。     

复方克林霉素脂质体凝胶的制备及体外透皮释药研究

目的制备复方克林霉素脂质体凝胶并考察其粒径分布、包封率及体外透皮特性。方法采用薄膜分散法制备复方克林霉素脂质体,利用透射电镜观察其形态,用激光纳米粒度仪测定其粒径大小及分布,用HPLC法测定其包封率。将脂质体进一步制成凝胶剂后,考察其体外透皮情况。结果复方克林霉素脂质体的粒径在240nm左右,分布均匀,平均包封率为51.24%;脂质体中的克林霉素能缓慢透过大鼠皮肤,缓释效果明显。结论该制剂制备工艺简单,性质稳定,药物包封率较高,定量测定方法简便、准确;药物透皮速率缓慢,释药稳定。     

曲马多缓释多囊泡脂质体的制备和释放度影响因素研究

目的 制备包封率高和缓释作用好的PGE修饰的曲马多缓释缓释多囊泡脂质体,并与逆相蒸发法制备的曲马多普通脂质体比较其体外释药性能.方法 用复乳法制备曲马多缓释多囊泡脂质体;非火焰原子吸收分光光度法测定曲马多含量;磷脂酶试剂法测定脂质体中磷脂的浓度;测定包封率和体外释药性.结果 曲马多缓释多囊泡脂质体平均粒径为31.3μm,跨距为1.0;曲马多包封率可高达80%以上;曲马多缓释缓释多囊泡脂质体的体外释药符合一级释药规律,释药时间为72h,比逆相蒸发法制备的曲马多普通脂质体延长16.95（由原来为释药时间37.7h延长8.4倍推出）倍;经差示热分析发现辅助膜稳定剂有明显的膜稳定作用.结论 曲马多缓释多囊泡脂质体包封率高,并具有良好的缓释作用.     

顺铂缓释多囊脂质体的制备和体外释放性能研究

目的 制备包封率高和缓释作用好的顺铂缓释多囊脂质体,并与反相蒸发法制备的顺铂普通脂质体比较其体外释药性能。方法 用复乳法制备顺铂多囊脂质体,非火焰原子吸收分光光度法测定顺铂含量,磷脂酶试剂法测定脂质体中磷脂的浓度。测定包封率和体外释药性。结果顺铂多囊脂质体平均粒径为16.6 μm,跨距为1.0。顺铂包封率可高达80%以上。顺铂缓释多囊脂质体的体外释药符合一级释药规律, 释药t_1/2为37.7 h,比反相蒸发法制备的顺铂普通脂质体延长8.4倍。经差示热分析发现辅助膜稳定剂有明显的膜稳定作用。结论顺铂多囊脂质体包封率高,并具有良好的缓释作用。     

氨溴索脂质体的制备及理化性质研究

目的制备氨溴索脂质体并考察其理化性质。方法采用硫酸铵梯度法制备氨溴索脂质体,在单因素考察基础上,采用正交试验设计优化脂质体的最佳处方和工艺;用透射电镜观察脂质体的外观形态,激光散射测定ξ电位和粒度分布,UV法测定脂质体的包封率,动态膜透析法探讨氨溴索脂质体体外释药特性。结果药物孵化时的形式、孵化温度、孵化时间是影响氨溴索脂质体包封率的主要的工艺因素,正交试验设计优化的最佳处方为磷脂与胆固醇之比8∶1、药脂比为1∶8、硫酸铵浓度为0.2 mol/L,最佳处方制备的脂质体为封闭的多层囊状或多层圆球体,大小均匀,平均粒径为7.189μm,ξ电位为+10.13 mv,包封率为80%,体外释放符合双向动力学方程(rα=0.998 1和rβ=0.992 3)。结论采用硫酸铵梯度法制备的氨溴索脂质体,包封率较高,体外释药有明显的缓释效果。     

P物质多囊脂质体的制备工艺优化及相关性质考察

目的:优化P物质多囊脂质体的制备工艺,并考察其相关性质。方法:复乳法制备P物质多囊脂质体,以包封率为指标,磷脂与胆固醇的摩尔比(A)、超声乳化时间(B)、初乳与二相小的体积比(C)、辅助乳化剂的浓度(D)为因素进行正交试验设计,优化其制备条件;对优化条件所制脂质体进行包封率、粒径分布、体外释药性能、相转变温度和熔点的考察。结果:优化制备条件A为2:1,B为30 s,C为1:2,D为2%;所制多囊脂质体包封率可达85%,粒径分布为0.75～27.75μm,在生理盐水中释药t_(1/2)=11 h,可持续72 h释药,相转变温度为34℃,熔点为110℃。结论:所制P物质多囊脂质体包封率高,物理性能稳定,是一种较为理想的缓释制剂。     

槲皮素前体脂质体的质量考察

目的制备液体型槲皮素前体脂质体,并对制剂质量进行考察。方法采用一种新型前体脂质体制备方法制备液体型槲皮素前体脂质体,将脂质体膜材和药物等以一定比例溶于分散介质中,形成一种无水的澄明溶液。考察其水合后粒子形态、粒径、电位、包封率及自组装速度等理化性质,并评价其体外释药性质。结果槲皮素前体脂质体遇水即可快速自组装成纳米级含药脂质体混悬液,水合后形态多为类球形,平均粒径为228.7nm,Zeta电位为21.2 mV,包封率可达90%以上,体外释药符合Higuchi方程。结论槲皮素口服前体脂质体制备工艺简单可行,包封率高,具有一定的缓释效果。     

饱和磷脂脂质体的室温下制备及其性质的研究

目的考察室温下用饱和磷脂制备脂质体的新方法(加入特殊的附加剂)及其对以蛋白多肽类为主药的包封情况,并研究了脂质体的体外性质。方法通过加入特殊的附加剂,用反相蒸发-超声分散法制备脂质体,并初步考察了其室温放置的稳定性;以尿激酶为例,考察所得脂质体的粒度分布和形态;对不同的蛋白多肽类药物进行包封;以阿霉素为模型药物,考察脂质体在PBS和小牛血清中的泄漏。结果附加剂DSPE-PEG 2000只需1%的用量(占磷脂的摩尔比),即可用饱和磷脂在室温下超声1 min制得脂质体;所得脂质体平均粒径在100 nm以下,形态圆整,室温放置稳定;对胰岛素和水蛭素的包封率与普通脂质体相近(23%),对尿激酶包封率高达(65.4±2.6)%;体外泄漏缓慢。结论提出的制备方法条件温和,产品稳定性好,非常适合高分子量蛋白类药物,并可获得较高的包封率,是一种很有前景的脂质体制备方法。     

槐定碱/苦参碱二元醇脂质体不同制备方法的比较

目的:以包封率、粒径分布和Zeta电位为指标,探讨槐定碱/苦参碱(sophoridine/matrine,S/M)二元醇脂质体3种不同制备方法的适宜性。方法:用被动载药法(Ⅰ法)、主动载药法(Ⅱ法)和被动加主动载药法(Ⅲ法)分别制备了S/M的二元醇脂质体,并考察了3种方法制备的不同药脂比二元醇脂质体的包封率、粒径分布和Zeta电位。结果:当药脂比为1∶1时,用Ⅰ法制备的S二元醇脂质体包封率最高,用Ⅲ法制备的M二元醇脂质体包封率最高;用Ⅱ法制备时,2种碱的包封率均随药脂比的减小而增大;而采用Ⅰ/Ⅲ法时2种碱的包封率均随药脂比的减小而减小。结论:制备S/M二元醇脂质体时,不同的方法和药脂比对其包封率有显著影响。S二元醇脂质体适宜用Ⅰ法制备,而M二元醇脂质体则适宜用Ⅲ法。     

肺靶向吡非尼酮脂质体的制备及体外释药性质研究

目的：研究肺靶向吡非尼酮脂质体的制备方法并考察其体外释药性质。方法：采用薄膜分散法制备吡非尼酮脂质体;用D-甘露糖修饰脂质体并添加适量十八胺调节脂质体表面电荷;用紫外分光光度法测定包封率;用正交实验优化处方,用透析法考察药物体外释放性质。结果：制得的脂质体平均粒径为581.1nm,表面电荷为-20.61mV,包封率为81.1%,稳定性好。药物体外释药符合Weibull方程。结论：采用薄膜分散法,用D-甘露糖修饰并添加十八胺可制得具有较高包封率及稳定性的吡非尼酮脂质体,有助于提高吡非尼酮的肺靶向性。     

Increased tumor cisplatin levels in heated tumors in mice after administration of thermosensitive, large unilamellar vesicles encapsulating cisplatin

Hyperthermia (HT)-dependent cisplatin (CDDP) release and tumor CDDP level increase after the administration of thermosensitive, large unilamellar vesicles (LUVs: LUV-1 and LUV-2) and a thermosensitive, small unilamellar vesicle (SUV: SUV-1) were examined in comparison with those following administration of a non-thermosensitive LUV (LUV-3) and a CDDP solution (Sol) in tumor bearing mice. The LUV-1 and LUV-2 released CDDP at a faster rate than SUV-1 when incubated in saline at temperatures between 41 and 44 degrees C. The blood CDDP levels after liposome administration were higher than those after Sol administration. The systemic clearance of LUV-2 was slightly larger than those of the other liposomes. The tumor CDDP levels after thermosensitive liposome administration were increased in response to HT in comparison to LUV-3 or Sol. The increased ratio for LUV-1 was the largest. The ratio of the area under the tumor CDDP level versus time curve (AUC) for LUV-1 + HT to the AUC for Sol + HT was approximately 5. The results indicate that (1) the tumor-CDDP level increase after thermosensitive liposome administration is due to CDDP release from the liposome in the blood at or adjacent to the heated tumor, (2) the increase is highly dependent on the heat sensitivity and systemic stability of the liposome, and (3) LUV, such as LUV-1, exhibit higher heat sensitivity and larger, targeted drug delivery efficiency than SUV.     

Effect of surface ligand density on cytotoxicity and pharmacokinetic profile of docetaxel loaded liposomes

Various biotin-modified liposomes incorporated with docetaxel (DTX) were prepared to study the effect of surface biotin density on the pharmacokinetic profile of the liposome. Four types of liposomes such as PEG modified liposome (PDL), 0.5% (mol) biotin modified liposome (0.5BDL), 1% (mol) biotin modified liposome (1BDL) and 2% (mol) biotin modified liposome (2BDL) were prepared using thin film dispersion method. The prepared liposomes were characterized by measuring encapsulation efficiency (EE), particle size, Zeta-potential, physical stability and drug release profiles in vitro. MTT assay was performed to elevate the cytotoxicity of liposomes on MCF-7 cells. In vivo evaluation was further performed to investigate the effect of biotin surface density on the pharmacokinetic profiles. All the prepared liposomes exhibited high encapsulation efficiency, small particle size, narrow particle distribution and sustained release profiles in vitro. In MTT assay, 0.5BDL showed largest tumor cell toxicity, compared with DTX solution. All liposomes containing DTX showed prolonged blood circulation in vivo, and 0.5BDL showed the longest circulation time among the biotin modified liposome. Surface modification of liposome had a negative impact on the circulation of liposomes in the blood, which needs to be considered when designing the ligand mediated targeting delivery systems. A proper amount of biotin liposome with 0.5% molar ratio is expected to produce the best anti-tumor effect.     

Effects of loading procedures of magnetic nanoparticles on the structure and physicochemical properties of cisplatin magnetic liposomes

The effects of different loading procedures of magnetic nanoparticles (MNs) on the structure and physicochemical properties of cisplatin magnetic liposomes were investigated by X-ray diffraction, infrared spectroscopy, transmission electron microscopy, and fluorescence spectroscopy. 1, 2-Dipalmitoyl-sn-glycero-3-Phosphocholine based cisplatin magnetic liposomes were prepared using two different procedures. In procedure I, MNs were combined with phospholipids during film formation; MNs were embedded in a phospholipid bilayer. In procedure II, MNs were mixed with drugs during hydration and MNs were contained in an interior aqueous compartment. The encapsulation efficiency of cisplain and the content of MN in procedure I liposomes were 33.5%?±?3.3% and 2.34?±?0.09?mg?mL^?1, respectively. It indicated that the deliberate MN loading into the liposome structure was not only successful using procedure I, but also superior over procedure II both in cisplatin encapsulation efficiency and MN content, which can promote the magnetic targeting effect of magnetic liposomes during delivering cisplatin.     

支链淀粉修饰双嘧达莫脂质体的制备及其在小鼠体内的组织分布

目的研究支链淀粉修饰双嘧达莫(DIP)脂质体的制备方法并考察其在小鼠体内的组织分布。方法 采用薄膜-分散法制备普通DIP脂质体；合成两亲性的棕榈酰化支链淀粉并用其修饰DIP脂质体；比较修饰前后包封率、zeta电位、平均粒径和径距的变化；采用反相高效液相法测定小鼠组织中的DIP浓度。结果修饰后DIP脂质体的包封率降低，zeta电位增加，平均粒径和径距无明显变化；普通脂质体可以增强DIP在肺部、肝脏和脾脏的分布，而较之普通脂质体，支链淀粉修饰的脂质体可以进一步增加肺部DIP水平，同时减少DIP在肝脏和脾脏的分布，并延长在肺部的滞留时间。结论与普通脂质体和注射液比较，支链淀粉修饰的脂质体可以改变DIP在小鼠体内的组织分布，具有显著的肺靶向性。     

Toxicity and anti-tumor activity of hydrophobic diammine and diaminocyclohexane platinum complexes entrapped in multilamellar vesicles

The toxicity and anti-tumor activity of a lipophilic diaminocyclohexane (DACH) platinum complex entrapped in liposomes (liposomal-cis-bis-neodecanoato-trans-R, R-1, 2-DACH platinum II-L-NDDP) were compared with those of the liposomal preparation of the same compound without the DACH group (liposomal-cis-bis-neodecanoato-(diammine) platinum II-L-CNDP). Both liposomal preparations had the same liposome size distribution, drug entrapment efficiency (greater than 95%), and liposome stability (greater than 95%). Although no differences were observed in the mouse LD50 (60.2 mg/kg for L-NDDP vs 67.8 mg/kg for L-CNDP), the liposome entrapped non-DACH compound (L-CNDP) was more nephrotoxic than the liposome entrapped DACH compound (L-NDDP), but much less than cisplatin (CDDP) (mean BUN elevation 4 days after the administration of the LD50 dose 67 mg% for L-CNDP vs 30 mg% for L-NDDP vs 255 mg% for CDDP). L-NDDP was not cross-resistant with CDDP against L1210/CDDP leukemia while L-CNDP was cross-resistant (%T/C 200 for L-NDDP, 112 for CDDP, and 100 for L-CNDP). In addition, L-NDDP was slightly more active than L-CNDP against i.p. L1210/0 leukemia and i.v. M5076 reticulosarcoma. These studies suggest that the attachment of a cyclohexane group to the amino functions of lipophilic platinum complexes results in a decrease of the nephrotoxicity and a lack of cross-resistance with CDDP. The lack of cross-resistance is preserved when the compounds are entrapped and delivered in a liposomal carrier but not when they are delivered in a micellar suspension.     

超氧化物歧化酶脂质体在大鼠体内的药代动力学和组织分布

目的考察3种超氧化物歧化酶(SOD)脂质体静脉给药后在大鼠体内的药代动力学和组织分布。方法 用反相蒸发法制备SOD脂质体，采用黄嘌呤氧化酶法检测SOD活力，静脉注射给药后，测定大鼠血中SOD含量变化和不同组织中SOD含量变化。结果在血浆中，SOD水溶液、SOD普通脂质体、用DSPE-PEG2000修饰的SOD脂质体、用Tween 80修饰的SOD脂质体的半衰期分别为0.25，0.34，0.66和0.41 h；AUC分别为12.48，24.66，41.16和33.02 μg·h·mL^-1。与普通脂质体比较，经过DSPE-PEG和Tween 80修饰后的脂质体，使肝、脾中SOD的含量有不同程度的降低，脑中含量有所提高。结论3种SOD脂质体均可不同程度地延长SOD的血浆半衰期，并以用DSPE-PEG2000修饰的SOD脂质体效果最好。与普通脂质体相比，用Tween 80修饰的SOD脂质体可以提高进入脑中的SOD量，用DSPE-PEG2000修饰的SOD脂质体可以减少肝脾对SOD的摄取。     

PEG修饰鳖甲肽HGRFG脂质体的药动学研究

目的 制备鳖甲肽HGRFG脂质体以及聚乙二醇（polyethylene glycol,PEG）修饰后的长循环脂质体,考察经修饰的脂质体较未修饰脂质体在动物体内分布及滞留情况。方法 采用BLB/c裸鼠荧光活体成像实验,进行脂质体体内分布及代谢研究;采用药动学实验,初步探究2种载药脂质体在血浆内的滞留时间。结果 2种载药脂质体均能广泛分布于实验动物体内。与未经修饰的脂质体载药组相比,经PEG修饰的长循环脂质体载药组中裸鼠荧光全部消失的时间明显延长,药物在血浆滞留时间也明显延长。结论 经PEG修饰后的长循环脂质体可以延长药物在实验动物体内的滞留时间,延长药物半衰期。     

Uptake of liposomes by cultured cardiomyocytes

Small unilamellar liposomes (SUV) of different phospholipid/polymer composition were labeled with NBD-PC, which served as a bilayersituated fluorescence marker. Neonatal cardiomyocytes were incubated with liposomes and then the cell-associated fluorescence was measured. The factors influencing the liposome uptake by cardiomyocytes such as concentration of lipid, time of incubation, membrane fluidity of liposomes, charge lipid/polymer modification of liposomes and anoxia of cultured cardiomyocytes were investigated. The liposome uptake by cardiomyocytes increased dose-dependently and time-dependently. Liposome uptake was strongly influenced by the electrical charge and modified polymer. After 2 h incubation, the uptake of positively charged liposomes was 1.7-fold higher than that of negatively charged one and both higher than that of the neutral one. The presence of PE-PEG2000 distinctly reduced the liposome uptake and the difference between the uptake of charged and neutral liposome. Anoxia increased the uptake of liposome at the first hour (increased 20%), but after 2 h incubation the liposome uptake by hypoxia cellswas less than that of normoxia cells (decreased 18%). Mechanisms involved are also discussed.     

Melittin liposomes surface modified with poloxamer 188: in vitro characterization and in vivo evaluation

Melittin liposomes surface modified with poloxamer 188 were developed, and the effect of poloxamer 188 was investigated with regard to anti-cancer effect and vascular stimulation. Melittin liposomes surface modified with poloxamer 188 at different concentrations (0%, 2%, and 5%) were prepared using the adsorption method, followed by in vitro characterization, including entrapment efficiency, zeta potential, particle size, and morphology. Subsequently, the influence of repeated freeze-thawing on the liposomes was investigated, and the effect of poloxamer 188 on the repeated freeze-thawing process was explored. Vascular stimulation effects of MLT, and MLT liposome that surface coated with or without poloxamer were all studied. Pharmacokinetics of the different MLT preparations were determined and the anticancer activity of the MLT formulations was investigated. The particle size of the liposomes gradually increased with increasing poloxamer 188 content, while the entrapment efficiency did not change significantly. After the first freeze-thaw cycle, size and PDI were both markedly reduced, entrapment efficiency rose, and there was no significant change of zeta potential. The vascular irritation caused by MLT could be reduced to an extent by encapsulation in liposome, but not completely eliminated, while liposomes coated with poloxamer 188 can effectively abolish the phenomenon. Melittin liposomes with surface modified by poloxamer exhibit enhanced bioavailability, effective anticancer activity, and reduced side effects compared with melittin solution. Poloxamer plays an important role in melittin liposomes.     

Rates of Systemic Degradation and Reticuloendothelial System (RES) Uptake of Thermosensitive Liposome Encapsulating Cisplatin in Rats

The systemic degradation and reticuloendothelial system (RES) uptake of cisplatin (CDDP)-encapsulated thermosensitive liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and di-stearoylphosphatidylcholine (DSPC) (DPPC/DSPC = 9/1, 7/3, and 5/5, w/w) after intravenous administration to rats were examined by measuring the platinum (Pt) levels in the blood and RES (liver and spleen). The blood liposome level profile showed first-order rate elimination for each liposome administration. The elimination rate (K _e1) was faster when the content of DSPC was lower (K _e1: 1.3/hr for 9/1-liposomes, 0.7/hr for 7/3-liposomes, 0.5/hrfor5/5-liposomes). On the other hand, the RES liposome level profile showed distribution of liposomes followed by elimination therefrom. The RES level of the liposomes was lower when the content of DSPC was smaller (maximal level: 25% for 9/1-liposomes at 1 hr, 32% for 7/3-liposomes at 1 hr, 37% for 5/5-liposomes at 2 hr). The kinetic analysis demonstrated that the RES uptake rate (K _res) was almost the same among the liposomes (0.4/hr), while the systemic degradation rate (K _deg; K _e1 – K _res) became larger as the content of DSPC decreased (0.9/hr for 9/1-liposomes, 0.3/hr for 7/3-liposomes, and 0.1/hr for 5/5-liposomes) and that the RES liposome distribution amount was dependent not only on the K _res but also on the K _deg and the rate of RES liposome degradation. The K _deg for each type of liposome corresponded with the systemic CDDP release rate.