PEG修饰脂膜对延长脂质体在血内循环时间的研究

研究目的是提高脂质体的稳定性,延长在血循环中的时间,增强在非RES部位的靶向性。将不同分子量的PEG-PE(聚乙二醇单甲醚磷脂酰乙醇胺衍生物)掺入脂质体,比较其在体外的稳定性和体内的分布情况。结果表明,该类脂质体在血循环中的滞留时间显著延长。并且与PEG的分子量有密切关系。本研究方法简便易行,从而省去同位素标记的困难,具有良好的应用前景。     

靶向递药系统长循环脂质体的研究进展

长循环脂质体作为一种新型的纳米载药系统,因其能实现血液中长滞留、高浓度靶向富集于病灶部位,在肿瘤的治疗中显示了独特的优势。通过查阅国内外相关文献并进行归纳总结,现就长循环脂质体及其制备方法、质量评价、药动学及药效学等进行综述。     

两种RGD肽修饰的新型阿霉素脂质体的体外表征

目的作为配体,肽对于多种受体显示出良好的靶向性,例如在肿瘤表面过度表达的整合素家族受体。本文主要研究和表征分别用精氨酸-甘氨酸-天冬氨酸(RGD)三肽和甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸(GRGDS)五肽修饰的载药脂质体。方法分别采用RGD和GRGDS对包载阿霉素的立体稳定脂质体(SSL-doxorubicin)进行修饰,以制备RGD-SSL-doxorubicin和GRGDS-SSL-doxorubicin。在体外表征试验中,测定了各种脂质体的包封率、粒径、Zeta电位和释放率,采用SRB试验研究了各脂质体对卵巢癌细胞的细胞毒作用,并应用流式细胞仪和共聚焦显微镜考察了肿瘤细胞对各脂质体包封的阿霉素的摄取情况。结果所有脂质体的包封率均在95%以上,采用RGD或GRGDS进行的修饰并未影响长循环脂质体的包封率。各种脂质体的平均粒径在105.7±3.5nm和130.5±3.0nm之间,Zeta电位在–3.3±0.3和–6.1±0.3mV之间,在模仿体内环境的释放介质(含胎牛血清)中,12小时内约有2/5的阿霉素从脂质体中释放。与游离阿霉素相比,修饰后的脂质体对肿瘤细胞的抑制率略有下降;在研究对阿霉素摄取的流式细胞试验和共聚焦试验中,也有类似现象出现。将各种脂质体分别加入肿瘤细胞后,阿霉素主要分布于SKOV-3的细胞核。结论本研究成功制备了两种分别用精氨酸-甘氨酸-天冬氨酸(RGD)三肽和甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸(GRGDS)五肽修饰的阿霉素脂质体。体外表征结果显示,该修饰不会显著改变立体稳定脂质体的性质。     

不同量羧甲基壳聚糖修饰紫杉醇脂质体对大鼠体内药动学的影响

目的:考察不同量羧甲基壳聚糖(CMCT)修饰紫杉醇脂质体后对大鼠体内药动学行为的影响。方法:大鼠尾静脉注射未修饰紫杉醇脂质体,0.1%CMCT修饰紫杉醇脂质体及0.2%CMCT修饰紫杉醇脂质体,血浆处理以炔诺酮为内标,叔丁基甲醚提取。检测波长227 nm,甲醇-水65 35为流动相,ODS-C18柱进行分析。结果:未修饰紫杉醇脂质体,0.1%CMCT修饰紫杉醇脂质体及0.2%CMCT修饰紫杉醇脂质体血浓经时曲线均符合二室模型,t1/2β分别为11.2、15.6、30.6 h,AUC0-1440分别为2541.99、2748.783、451.64 mg.L-1.min。结论:羧甲基壳聚糖修饰后紫杉醇脂质体的大鼠体内药动学行为有明显的改变,消除半衰期和血中的循环时间均有不同程度的延长,AUC增加,且与其用量有一定的相关性。     

表面带活性羧基的新型长循环脂质体的制备和组织分布研究

合成和纯化了一个带末端羧基的新的磷脂酰乙醇胺的聚乙二醇衍生物－DPPE－PEG3000－COOH。将这个化合物掺入脂质体后，脂质体在网状内皮系统（肝，脾）的聚集减少，在血中的循环时间明显延长，并表现为一级对数线性消除。脂质体表面的活性羧基可以和其它活性分子反应，这可能为脂质体带来新的功能。     

伏立康唑长循环脂质体的制备及在大鼠体内药动学研究

摘 要 目的：制备伏立康唑长循环脂质体,并考察其在大鼠体内药动学特性。方法: 采用薄膜分散 挤压法制备伏立康唑长循环脂质体,并分别考察长循环脂质体在磷酸盐缓冲液和大鼠血浆中的释放情况,评价长循环脂质体在冻干前后的粒径分布、形态等理化性质;测定伏立康唑长循环脂质体在大鼠体内的药动学行为。结果: 所制备的伏立康唑长循环脂质体的平均粒径为（192.1±49.3）nm,呈球形或类球形分布;在磷酸盐缓冲液(PBS)中释放缓慢,而在大鼠血浆中释放较快;大鼠体内药动学表明,伏立康唑长循环脂质体的t1/2及AUC0 t分别为伏立康唑注射剂的2.17和2.31倍。结论:伏立康唑长循环脂质体延长了药物在血浆中的滞留时间,能达到长循环目的。     

葡萄糖修饰的不同PEG作为桥联脂质体的体外特性研究

目的 制备用葡萄糖修饰以不同聚合度的PEG作为桥联的脂质体,并考察其体外特性.方法 以香豆素6为荧光探针,用薄膜分散法制备葡萄糖修饰的以PFG400、PEG800、PEG2000作为桥联的载香豆素6脂质体,用激发光散射粒度测定仪测定其粒径;用凝胶柱层析法测定其包封率;在含10%胎牛血清的磷酸盐缓冲液（PBS）中考察其稳定性;以大鼠脑毛细血管内皮细胞（BCECs）为受试细胞,对载香豆素6的不同类型脂质体进行细胞摄取的定量分析.结果 葡萄糖修饰的以PEG400、PEG800、PEG2000作为桥联的脂质体的粒径分别为（81.5±6.3）、（100.0±5.0）、（104.9±8.7）nm,多分散系数（PDI）分别为（0.252±0.016）、（0.265±0.032）、（0.289±0.013）;其包封率均〉80%;在含10%胎牛血清的PBS中具有较好的稳定性;葡萄糖修饰的以PEG800、PEG2000作为桥联的脂质体在BCECs中的细胞摄取率均高于普通脂质体.结论 本研究成功制备了葡萄糖修饰的以PEG400、PEG800、PEG2000作为桥联的脂质体,研究初步显示以PEG800、PEG2000为桥联的脂质体有一定脑靶向潜力.     

7-乙基-10-羟基喜树碱长循环脂质体的制备及药动学研究

目的:研究7-乙基-10-羟基喜树碱长循环脂质体(Lip-SN38)的制备方法以及在大鼠体内的药动学.方法:采用两步合成法制备脂质体空间稳定膜材甲氧基聚乙二醇.磷脂酰乙醇胺(mPEG-PE);同时采用薄膜分散法制备Lip-SN38;用阳离子交换树脂微型小柱层析法分离游离药物和脂质体,紫外分光光度法测定包封率;HPLC法测定大鼠血浆中药物浓度.结果:Lip-SN38平均粒径<200 nm,药物包封率>90%;48 h只有<30%的药物体外释放;大鼠尾静脉注射Lip-SN38,剂量为10 mg·kg-1,与SN3.8溶液剂相比,t1/2β增加4.61倍.结论:采用薄膜分散法可制得包封率高、粒径小的脂质体,mPEG-PE修饰磷脂膜可增加Lip-SN38的t1/2β,延长药物在血中的循环时间.     

多西他赛长循环脂质体的制备与大鼠体内药动学评价

摘 要 目的：制备多西他赛长循环脂质体,并评价大鼠尾静脉给药的药动学特性。方法: 采用薄膜分散 挤出法制备多西他赛长循环脂质体,并对其粒径分布、Zeta电位和微观形态进行表征。将12只Wistar大鼠随机分为多西他赛注射液组和多西他赛长循环脂质体组,尾静脉给药剂量均为7.5 mg·kg^-1,采用HPLC法测定大鼠血中多西他赛的药物浓度,采用3P97程序计算多西他赛大鼠体内药动学参数。结果: 多西他赛长循环脂质体平均粒径为（109.2±28.6）nm,Zeta电位为（-15.8±2.7）mV。多西他赛注射液和多西他赛长循环脂质体在大鼠体内的t_1/2(α)分别为（0.19±0.05）h和（0.36±0.07）h;t_1/2(β)分别为（1.82±0.33）h和（17.93±1.37）h;AUC_0-t分别为（4.42±0.76）μg·mL^-1·h^-1和（33.73±3.52）μg·mL^-1·h^-1。结论:多西他赛长循环脂质体与市售多西他赛注射液相比,延长了药物在血浆中的滞留时间,能达到长循环目的。     

聚乙二醇修饰的立体稳定脂质体

立体稳定脂质体（长效脂质体）是一种表面含有天然或合成聚合物修饰的类脂衍生物的新型脂质体。它在血液中驻留时间延长，从而延长药物作用时间，具有长效作用。将抗体或其他配体连接于长效脂质体表面的聚合物末端，可得到立体稳定的免疫脂质体，从而达到长效与靶向的完善结合。     

鳖甲多肽的全合成及对肝星状细胞的作用

目的 研究鳖甲多肽的合成及对肝星状细胞(hepatic stellate cell, HSC)的作用. 方法 根据鳖甲活性多肽的序列结构,采用Fmoc固相 方法 对多肽进行全合成,经反相高效液相色谱法分析、纯化获得合成多肽;不同浓度合成多肽作用肝星状细胞株HSC-T6 24 h,用Annexin V-FITC/PI法检测HSC凋亡. 结果 反相高效液相纯化后合成多肽的纯度＞98.0%,经质谱鉴定其相对分子质量与理论值一致;合成多肽浓度为0.6 mg.mL^-1时,早期凋亡细胞开始增多,至2.5 mg.mL^-1时,坏死细胞开始增多,随合成多肽浓度增高,各组凋亡细胞随之增多. 其中鳖甲合成多肽在1.2,2.5和5 mg.mL^-1浓度下能显著提高HSC早期凋亡率(P<0.05). 结论 鳖甲多肽可以定向合成,并且合成多肽能诱导HSC的早期凋亡.     

鳖甲汤鳖甲先煎的试验研究

目的:探讨影响鳖甲汤中氮含量的因素。方法:采用正交试验方法对鳖甲汤中的氮含量进行测定。结果:鳖甲的粉碎度和煎煮时间对鳖甲汤中氮含量的影响均有显著性差异。结论:鳖甲入汤剂以粉碎过60目筛、加10倍量水、先煎1.5小时为宜。     

紫杉醇脂质体大鼠体内药动学考察

目的 使用HPLC-UV法测定大鼠体内紫杉醇血药浓度,考察紫杉醇脂质体在大鼠体内药动学。方法 大鼠尾静脉注射紫杉醇脂质体及紫杉醇注射液,血浆用叔丁基甲醚提取。ODS柱,流动相为甲醇水(65∶35),检测波长227nm。结果 本法在0.05～50μg·ml^-1范围内线性良好,日内、日间精密度RSD<6%,高、中、低3个浓度下提取回收率均大于90%。紫杉醇脂质体及紫杉醇注射液血药浓度经时曲线均符合二室模型。t_1/2β分别为(11.19±0.08)h和(7.49±0.80)h,AUC分别为2615.89±770.58(mg·L^-1·min^-1)和904.94±25.36(mg·L^-1·min^-1)。结论 与市售紫杉醇注射液相比,紫杉醇纳米脂质体有一定的长循环作用,且提高大鼠体内的利用度。     

紫杉醇脂质体大鼠体内药动学考察

目的使用HPLCUV法测定大鼠体内紫杉醇血药浓度,考察紫杉醇脂质体在大鼠体内药动学。方法大鼠尾静脉注射紫杉醇脂质体及紫杉醇注射液,血浆用叔丁基甲醚提取。ODS柱,流动相为甲醇水(65∶35),检测波长227nm。结果本法在0.05～50μg·ml-1范围内线性良好,日内、日间精密度RSD<6%,高、中、低3个浓度下提取回收率均大于90%。紫杉醇脂质体及紫杉醇注射液血药浓度经时曲线均符合二室模型。t1/2β分别为(11.19±0.08)h和(7.49±0.80)h,AUC分别为2615.89±770.58(mg·L-1·min-1)和904.94±25.36(mg·L-1·min-1)。结论与市售紫杉醇注射液相比,紫杉醇纳米脂质体有一定的长循环作用,且提高大鼠体内的利用度。     

Pharmacokinetics of PEG-Hemoglobin SB1, a hemoglobin-based oxygen carrier,after its intravenous administration in beagle dogs

The purpose of the present study was to investigate the pharmacokinetics of PEG-hemoglobin SB1, a modified bovine hemoglobin with polyethylene glycol, after its single and multiple administration in beagle dogs. For this purpose, the analytical method of free hemoglobin in the plasma was developed and validated. Excellent linearity (r2=0.999) was observed in the calibration curve data, with the limit of quantification of 0.005 g/dL. The precision and the deviation of the theoretical values for accuracy were always within +/-15% in both the between- and the within-day results. The method was tested by measuring the plasma concentrations following intravenous administration to beagle dogs and was shown to be suitable for pharmacokinetic studies. In a single dose study, the plasma half-life (t1/2) increased and the total body clearance (CLt) decreased with the dose (i.e., 0.017 to 0.75 gHb/kg as PEG-hemoglobin SB1) in both sexes. The volume of distribution at steady-state (Vd(ss)) showed no difference with the dose. In contrast, the values of t1/2, CLt and the area under the plasma concentration-time curve (AUC) after the multiple dose were significantly different from those of the single dose administration. The values of t1/2 in the multiple administration were about two times higher than that of the single dose. As a result, t1/2 of hemoglobin after the administration of PEG-hemoglobin SB1 was about 15-30 h, indicating the PEG modification of the hemoglobin lead to a prolongation of plasma concentration of the protein. Therefore, these observations suggested that the PEG modification of hemoglobin is potentially applicable in the hemoglobin-based therapeutics.     

8-氯腺苷长循环脂质体的制备及其在大鼠体内的药代动力学

Aim To prepare 8-chloro-adenosine (8-Cl-A) long circulation liposomes with high entrapped efficiency and prolonged action-time of 8-Cl-A in vivo. Methods To prepare 8-Cl-A long circulation liposomes of Manometer size by improved multiple emulsion. The entrapped efficiency, size and size distribution of 8-Cl-A long circulation liposomes were determined, and its pharmacokinetics in rats was evaluated. Results The entrapped efficiency of 8-Cl-A long circulation liposomes was 62.70% and mean diameter of the liposomes was 79.9 rim. The pharmacokinetics studies indicated that 8-Cl-A long circulation liposomes showed higher drug concentration and larger AUC values than that of 8-Cl-A after iv to rats. Conclusion 8-Cl-A long circulation liposomes could prolong the action-time of 8-Cl-A in vivo.     

Development of a Novel Bioactive Formulation of Vasoactive Intestinal Peptide in Sterically Stabilized Liposomes

Pharmaceutical Research -     

Effect of Liposome Characteristics and Dose on the Pharmacokinetics of Liposomes Coated with Poly(amino acid)s

Long-circulating liposomes, such as PEG-liposomes, are frequently studied for drug delivery and diagnostic purposes. In our group, poly(amino acid) (PAA)-based coatings for long-circulating liposomes have been developed. These coatings provide liposomes with similar circulation times as compared to PEG-liposomes, but have the advantage of being enzymatically degradable. For PEG-liposomes it has been reported that circulation times are relatively independent of their physicochemical characteristics. In this study, the influence of factors such as PAA grafting density, cholesterol inclusion, surface charge, particle size, and lipid dose on the circulation kinetics of PAA-liposomes was evaluated after intravenous administration in rats. Prolonged circulation kinetics of PAA-liposomes can be maintained upon variation of liposome characteristics and the lipid dose given. However, the use of relatively high amounts of strongly charge-inducing lipids and a too large mean size is to be avoided. In conclusion, PAA-liposomes represent a versatile drug carrier system for a wide variety of applications.