肝靶向米托蒽醌白蛋白微球的研究

用乳化—热固化法制备了米托蒽醌白蛋白微球,并对其形态、大小及其分布、微粉学性质、载药性能、体外释药、稳定性和体内分布进行了研究。结果表明,该载药微球的平均算术径为0.99μm,平均表面径为1.24μm,平均容积径为1.44μm;表观载药量为2.558%±0.101%;有效载药量为1.503%±0.127%;包封率为92.82%±4.60%;体外释药符合双相动力学规律,释药方程为1-Q=0.6428e^-0.2132t+0.3988e^-000150t(γ₁=-0.9951,γ₂=-0.9982);T_1/2α=3.250h,T_1/2β=461.7h;室温放置3个月,微球形态、药物含量等均无明显变化。HPLC测定表明,小鼠尾iv该微球20min内即有77.6%±1.38%的药物浓集于肝脏,具有明显的肝靶向性。提示米托蒽醌白蛋白微球有可能提高米托蒽醌的抗肝癌效果和降低其全身毒副作用。     

米托蒽醌白蛋白微球和糖蛋白微球的体外释药规律

目的：考察米托蒽醌白蛋白微球和米托蒽醌联糖白蛋白球的体外释药规律。方法：采用动脉透析法释药,分光光度法测定米托蒽酯含量。结果：二者在体外释药符合双指数双相动力学规律,但后者达释药平衡快（约6小时）,累积释放量几科比前者小一倍。结论：两种微球的累积药分数经单因数经单因数经方差分析,具有显著差异。     

联糖米托蒽醌白蛋白微球的制备及其性质研究

以米托蒽醌为模型药物，用乳化热固化法制备了米托蒽醌白蛋白微球。以Ｄ－半乳糖为原料，经溴代、缩合、转换、加成等反应合成了２－亚氨基－２－甲氧基乙基－１－硫化β－Ｄ半乳吡喃糖苷（ＩＭＥ－ｔｈｉｐｇａｌａｃｔｏｓｅ）。以此为中间体与米托蒽醌白蛋白微球在室温下反应制备了联糖米托蒽醌白蛋白微球及其冻干剂，并对冻干剂的形态，球径及其分布、再分散性、糖精密、载药量、体外释药特性进行了研究，为白蛋白微球与联糖白蛋     

肺靶向米托蒽醌明胶微球的研究

采用二步法制备米托蒽醌明胶微球,球径范围为5.1～25.0μm的占总数87.36%,体外释药与原药相比t1/2延长4倍,DTA曲线上的特征吸热峰为133℃,经37℃,RH75%考察3月,几乎无变化。经小鼠体内分布试验表明具有明显的肺靶向性,靶向效率增加3～35倍,肺中药代动力学行为可用一室开放模型描述,平均滞留时间延长10h。     

联糖米托蒽醌的趋肝性研究

目的：合成肝靶向药联糖米托蒽醌（ＮＧＡＤＨＡＱ）的趋肝性研究。方法：以合成配体半乳糖基拟糖白蛋白（ｎｅｏｇｌｙｃｏａｌｂｕｍｉｎ,ＮＧＡ）为载体,与抗癌药物米托蒽醌（ｍｉｔｏｘａｎｔｒｏｎｅ,ＤＨＡＱ）偶联得肝靶向抗癌药物ＮＧＡＤＨＡＱ。采用紫外光谱和ＨＰＬＣ确证其偶联的形式及在血液中的稳定性。用９９ｍＴｃ标记后进行家兔放射性显像及小鼠体内的分布实验。结果：ＮＧＡＤＨＡＱ为化学偶联物且在血中很稳定,家兔及小鼠肝中药物的量均在５ｍｉｎ时达最大,分别占全身放射量的６５．１％和６５．４％±４．３％（ｎ＝３）。结论：说明ＮＧＡＤＨＡＱ具肝靶向分布性。     

米托蒽醌毫微球在裸鼠人肝癌模型体内的靶向性研究

米托蒽醌（ｍｅｔｏｘａｎｔｒｏｎｅ，ＤＨＡＱ）是近年合成的抗肿瘤新药〔１〕。国内外主要用于治疗白血病和乳腺癌，近年国外的临床研究证明其抗原性肝癌的效果亦较好，有开发价值〔２，３〕。有研究ＤＨＡＱ的水针剂静脉注射后虽有约４５％集中于肝脏，且心脏毒性较阿霉素低，但由于其浓集于肝脏的速度慢（约需６ｈ），故仍存在较大的毒性〔４，５〕。毫微球是一种新型药物载体。国外近十年来的研究证明能使药物快速地浓集于靶器     

白蛋白微球作为肝靶向给药载体的研究

用均匀设计方法和计算机技术筛选了乳化化学交联法制备白蛋白微球的六个因素,十二个水平。优化出最佳制备工艺,制备了平均粒径0.41～0.47μm的白蛋白微球。将此工艺制备的¹²⁵I-白蛋白微球做动物体内研究,结果表明微球iv后主要浓集在肝脏,可达注入总剂量的68%,此微球在靶组织肝脏的变化规律可用二室模型契合。     

米托蒽醌毫微球在裸小鼠人肝癌模型体内的靶向性研究

采用液体闪烁计数技术研究厂氖标记米托惠醌聚氰基丙烯酸正丁酯毫微球（￣（３）Ｈ－ＤＨＡＱ－ＰＢＣＡ－ＮＳ）在常位及异位（腋下）裸小鼠人肝癌模型体内各脏器、肌肉、肝常位肿瘤组织和腋下肿瘤组织中的分布。证明该制剂具有良好的肝靶向作用，肝脏中的含量为体内总药量的７１．３１±１０．４９％（ｎ＝５）。并发现其在常位肿瘤组织中的含量高于肝组织中的含量，腋下肿瘤组织中的含量高于腋下肌肉组织中的含量，但均无显著性差异。为该制剂的进一步研究提供了一定的科学依据。     

肝动脉栓塞米托蒽醌乙基纤维素微球的研究

利用正交实验设计法,优选适用于肝动脉栓塞的米托蒽醌乙基纤维素微球制备条件和工艺;采用动态透析法研究了该微球的体外释药规律;根据混悬液的稳定性理论,优选并制备了适于临床肝动脉介导栓塞使用的米托蒽醌乙基纤维素微球混悬注射液。结果表明∶在优化工艺条件下制得的米托蒽醌乙基纤维素微球外形圆整,球径在40～200μm范围内的占总数的91.9%,平均球径为110.24±38.19μm;包封率为55.6%;载药量为12.5%;体外释药符合单指数模型,释药方程为lg(Y_∞-Y)=-0.116t-1.198×10^-3(γ=0.9992,t₅₀=2.6h);其混悬液适于临床应用。用狗进行的实验表明肝血药浓度高,平均驻留时间比注射剂长2.45倍。     

去甲斑蝥素白蛋白微球在小鼠体内肝靶向作用

目的:研究去甲斑蝥素(NCTD)白蛋白微球在小鼠体内的组织分布、体外细胞毒性及肝靶向性。方法:采用体外细胞毒性和体内全身急性毒性试验方法,评价NCTD白蛋白微球的抗肿瘤活性及其生物安全性;通过小鼠尾静脉给药得到各主要药动学参数,并与NCTD注射液组比较得其靶向效率。结果:NCTD白蛋白微球在肝脏和肾脏的靶向效率分别为2.389 1和0.375 4。NCTD白蛋白微球体内外的生物安全性与其注射液比较无显著差异。体外细胞毒性显示其对肿瘤细胞具有特殊亲和力和靶向释药作用。结论:NCTD白蛋白微球具有肝脏靶向性,能降低肾脏分布,提高药物疗效,降低全身不良反应。     

Albumin nanostructures as advanced drug delivery systems

ABSTRACT

Introduction: One of the biggest impacts that the nanotechnology has made on medicine and biology, has been in the area of drug delivery systems (DDSs). Many drugs suffer from serious problems concerning insolubility, instability in biological environments, poor uptake into cells and tissues, sub-optimal selectivity for targets and unwanted side effects. Nanocarriers can be designed as DDSs to overcome many of these drawbacks. One of the most versatile building blocks to prepare these nanocarriers is the ubiquitous, readily available and inexpensive protein, serum albumin.

Areas covered: This review covers the use of different types of albumin (human, bovine, rat, and chicken egg) to prepare nanoparticle and microparticle-based structures to bind drugs. Various methods have been used to modify the albumin structure. A range of targeting ligands can be attached to the albumin that can be recognized by specific cell receptors that are expressed on target cells or tissues.

Expert opinion: The particular advantages of albumin used in DDSs include ready availability, ease of chemical modification, good biocompatibility, and low immunogenicity. The regulatory approvals that have been received for several albumin-based therapeutic agents suggest that this approach will continue to be successfully explored.     

Interaction of allylisothiocyanate with bovine serum albumin

The interaction of allylisothiocyanate with bovine serum albumin was monitored by “available” lysine estimation, electrometric and spectrophotometric titration, u.v. absorption and difference spectroscopy and electrophoresis. “Available” lysine estimation and electrometric titration indicated that the interaction increased with the reaction pH. Spectrophotometric titration indicated that at least two of the tyrosine groups became masked, probably via H-bonding, upon interaction of the protein with allylisothiocyanate. The pK_int values of the unreacted ?-amino groups of lysine and the titrable phenolic groups of tyrosine did not alter upon interaction. The electrophoretic mobility of the protein increased with the interaction. Difference spectral studies suggested thiourea formation.     

iRGD靶向载药脂质体-微泡复合物的制备及其靶向性研究

目的:制备iRGD靶向载药脂质体-微泡复合物,研究其靶向性。方法:采用薄膜-超声分散法制备生物素化的iRGD靶向载药脂质体和生物素化的超声微泡。利用生物素-亲和素系统(Biotin-avidin-system, BAS)连接脂质体与微泡,构建并表征iRGD靶向载药脂质体-微泡复合物。细胞黏附实验验证复合物的体外靶向结合性能;构建小鼠乳腺癌移植瘤模型,通过靶组织的药物荧光强度验证复合物的体内靶向性。结果:iRGD靶向载药脂质体的粒径为(165.07±4.01)nm,电位为(-12.92±0.26)mv,复合物的载药量为每10⁸个复合物载紫杉醇(46.22±1.95) μg;黏附实验表明靶向组复合物与血管内皮细胞结合数量明显多于非靶向组复合物(7.8±1.1,0.2±0.45,P<0.01);荷瘤小鼠活体成像实验显示靶向组复合物的肿瘤组织荧光明显强于非靶向组复合物。结论:iRGD靶向载药脂质体-微泡复合物,作为一种靶向给药系统,可以实现超声分子成像与超声给药的有机结合,显著提高药物靶向递送的效率。     

Enhanced liver targeting of 5-fluorouracil using galactosylated human serum albumin as a carrier molecule

The objective of this study was to develop a liver-specific antihepatocarcinoma agent. The galactosylated human serum albumin 5-fluorouracil conjugate (GHSA-5-FU) was prepared and tested for its chemical characteristic, biodistribution and primary cytotoxicity. The matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was applied to determined the molar ratio (moles of 5-FU/mole of G-HSA and moles of galactose/mole of HSA) of the conjugate. The liver targeting ability of GHSA-5-FU labeled by ¹³¹I was evaluated by measuring the total radioactivity in organs after i.v. administration in mice and rabbits, and the cytotoxicity of the conjugate was assayed by MTT method. The results showed that the molar ratio of galactose to HSA was 50, and the 5-FU to GHSA was 15. Liver uptake in rabbits and mice peaked within 5–20 min after injection. The radioactivity (counts/g tissue) of the conjugate in the liver was several times higher than those in the other organs. The conjugate showed strong cytotoxicity, but no significant cytotoxicity difference was found between GHSA-5-FU and free 5-FU.     

系列黄酮化合物与血清白蛋白结合及其结构相关性

目的比较具有不同取代基基团的八种黄酮类化合物与牛血清白蛋白(BSA)的相互作用及与其结构的相关性。方法基于黄酮化合物能够猝灭色氨酸残基的内源性荧光,采用荧光光谱法研究黄酮类化合物与BSA结合作用,根据荧光猝灭方程计算黄酮类化合物与BSA的表观结合常数(KA)和结合位点数。结果八种黄酮类植物化学物与BSA的结合强弱依次为:橙皮素(5.59×105)>槲皮素(4.94×105)>柚皮素(3.04×105)>异槲皮素(4.66×104)>淫羊藿苷(3.60×104)>芦丁(1.65×104)>橙皮苷(2.50×103)>柚皮苷(8.70×102)。结论糖苷基取代对黄酮类化合物与BSA的结合作用有很大影响,A环可能是黄酮类化合物插入BSA疏水区的关键部位,其C7位上的糖苷基取代是影响其与BSA结合的关键基团。此研究探讨了黄酮类化合物与BSA的作用及其与结构相关性规律,对了解黄酮类化合物在体内的运输、代谢和分布提供了一定实验依据。     

Microsomal Cytochrome P450 Levels and Activities of Isolated Rat Livers Perfused with Albumin

Purpose. We recently showed that the perfusion of isolated rat livers with perfusates containing bovine serum albumin (BSA) would significantly stimulate the release of tumor necrosis factor (TNF)-. Here, we hypothesize that BSA-induced increase in the release of TNF-, and possibly other cytokines, would affect cytochrome P450 (CYP)-mediated drug metabolism. Methods. Rat livers were perfused ex vivo for 1, 2, or 3 h with a physiologic buffer containing or lacking 1% BSA (n = 4-5/group). At the end of perfusion, liver microsomes were prepared and analyzed for their total CYP, CYP2E1, CYP3A2, and CYP2C11 protein contents and the activities of cytochrome c reductase, CYP2E1, CYP3A2, CYP2C11, CYP2E1, CYP2D1, CYP1A1, and CYP2B1/2. In addition, the concentrations of various cytokines and nitric oxide were quantified in the outlet perfusate. Results. In the absence of BSA, the perfusate levels of all measured cytokines and nitric oxide were low. However, when the perfusate contained BSA, the levels of TNF-, interleukin-6, and nitric oxide increased significantly (p < 0.005). Perfusion of the livers for 3 h with the BSA-containing perfusate resulted in significant (p < 0.05) decreases in the total CYP (41%), CYP2E1 (59%), CYP3A2 (68%), and CYP2C11 (50%) protein contents and activities of cytochrome c reductase (31%), CYP2E1 (66%), CYP3A2 (54%), and CYP2C11 (51%). In contrast, perfusion of livers for 1 or 2 h with the BSA perfusate did not have any significant effect on CYP-mediated metabolism. The CYP1A2, CYP2D1, and CYP2B1/2 activities were not affected by BSA, regardless of perfusion time. Conclusion. Addition of BSA to perfusates, which is a routine practice in isolated rat liver studies, can reduce CYP-mediated drug metabolism by a mechanism independent of protein-binding effect.     

木犀草素、芹菜素与牛血清白蛋白相互作用的研究

目的研究木犀草素、芹菜素与牛血清白蛋白(BSA)的相互作用机制。方法主要应用荧光猝灭法及非辐射能量转移原理。结果测得不同温度下，木犀草素、芹菜素与牛血清白蛋白的结合常数，确定两种黄酮小分子对牛血清白蛋白荧光的猝灭是静态猝灭过程，并依据能量转移原理求得其结合距离和能量转移效率。结论木犀草素、芹菜素与牛血清白蛋白间有较强的结合作用，且结合力以疏水作用力为主；B(3′)-OH，B(4′)-OH邻位对黄酮与牛血清白蛋白的结合具有增强作用。