注射用硫酸链霉素白蛋白微球的研究

用分散剂法制备了链霉素白蛋白微球,并测定了微球一些物理性质包括微球大小、分布与表面状态。结果表明微球在10～30μm范围内,药物含量为20.3±0.16%。完成了体外释药试验,同时用荧光素异硫氰酸盐与¹²⁵Ⅰ标记微球进行大鼠体内分布实验。实验证实微球主要集中在肺组织,这对于提高链霉素的疗效降低其毒副作用有重要的意义。     

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。     

去甲斑蝥酸钠白蛋白微球的研究

选择去甲斑蝥酸钠为模型药物,对含药白蛋白微球的制备、载药性能、形态、表面状态、大小及分布、体外释药、冷冻干燥、⁶⁰Co辐照灭菌和稳定性等进行了研究。结果表明,去甲斑蝥酸钠微球的平均大小为0.43±0.12μm,药物含量为20.34～26.75μg/ml,包入率21.9～26.4%,体外释药符合Higuchi方程,冷冻干燥和⁶⁰Co辐照对微球无影响且能达到无菌要求,放置3个月后微球的稳定性良好。     

胸腺肽α1缓释注射微球的研究

制备胸腺肽α₁(Tα₁)的长效注射微球，并对微球的体外释放特性、体外活性及药效学进行考察。采用复乳法(W/O/W)制备了载Tα₁聚乳酸-羟基乙酸嵌段共聚物(PLGA)的微球；考察微球的粒径大小、外观及包封率等理化特性；以HPLC法测定微球的体外释放速率；采用CCK-8法评价微球制备工艺和体外释放过程中Tα₁的生物学活性；体内药效学研究中采用流式细胞仪检测免疫抑制模型大鼠给予Tα₁微球后所产生的CD₄⁺，CD₈⁺因子的量，根据CD₄⁺/CD₈⁺的比值变化评价体内药效。微球球形圆整，分散性好，两个优选处方(外水相中加入5%氯化钠和10%葡萄糖)的微球包封率分别为87.8%和90.2%；Tα₁微球1个月的体外累积释放可达90%以上。使用含10%葡萄糖的PVA溶液作为外水相，较好地保持了制备工艺过程中的Tα₁生物学活性，在体外释放过程中Tα₁的生物学活性略有下降；Tα₁微球可显著提高免疫抑制模型小鼠的免疫力。用可生物降解的聚合物PLGA作为载体材料，可以将Tα₁制备成缓释1个月的注射微球。     

斑蝥素白蛋白微球制备工艺的优化

目的优化斑蝥素白蛋白微球的制备工艺,并对其形态学性质、载药量进行考察.方法以加热固化法制备微球,以均匀设计考察影响因素.结果微球平均粒径为(0.91±0.16)μm,载药量为(15.32±1.15)%.结论优化后工艺较合理,所制得微球形态圆整、均匀,载药量较高.     

新型左心声学超声造影剂空气白蛋白微球制剂的研制

目的 :对空气人血白蛋白微球制剂的制备工艺进行研究 ,并初步探讨微球形成机理。方法 :按正交设计筛选最佳制备工艺条件 ;库尔特颗粒分析仪测定最佳制备工艺条件下微球粒径 ;光、电镜考察微球外观形态。结果 :最佳制备工艺 :白蛋白生理盐水溶液浓度为5 % ,声振仪功率为9档 ,声振持续时间为60秒。结论 :通过正交试验设计 ,成功研制出含空气的白蛋白微球 ,并能有效地用于左心靶向超声显影诊断     

肝动脉栓塞用顺铂白蛋白微球的研究

按正交设计筛选乳化热固化法制备顺铂白蛋白微球的最佳工艺,并对影响微球粒径大小和体外释药速率的诸多因素进行了研究。该微球粒径范围为50.8～256μm。平均粒径为148.46μm,药物含量为51.16%(W/W)。兔肝动脉栓塞后,与对照组相比铂的分布半衰期延长336%,消除半衰期延长123%,体内最高血浓仅为对照组的30%。肝组织顺铂量显著增加(P<0.01),肾组织药物量明显降低(P<0.05),体内外相关性研究表明顺铂白蛋白微球体外累积溶出百分率与兔体内药物吸收分数呈显著相关(P<0.01)。     

褪黑激素明胶微球的鼻腔给药

目的　制备经鼻粘膜给药的褪黑激素明胶微球,以提高其生物利用度。方法　用乳化交联技术制备褪黑激素明胶微球,用放射性核素^99mTc标记,用γ射线闪烁显像技术考察微球在鼻粘膜滞留时间,用HPLC法测定药物的体内吸收。结果　褪黑激素明胶微球粒径在30～70 μm,平均粒径为50.2 μm,褪黑激素含量为13.48%。与滴鼻液相比,明胶微球在鼻粘膜滞留时间明显延长。褪黑激素明胶微球的绝对生物利用度为87.47%。结论　鼻粘膜给药明胶微球,能避免肝脏首过作用,延长药物在鼻粘膜滞留时间,提高药物吸收,有很好的应用前景。     

苦参碱白蛋白微球的制备及性质

以乳化-化学交联法制备苦参碱白蛋白微球。采用扫描电镜、差示扫描量热法和X-射线衍射法考察微球的特性,并用动态透析法考察体外释药规律。所得微球外观圆整,包封率为(83.55±3.17)%,载药量为(6.19±0.24)%,平均粒径(0.94±0.15)μm。体外释放试验结果显示,苦参碱白蛋白微球具有明显的缓释作用。     

去甲斑蝥素白蛋白微球的制备

目的:对去甲斑蝥素白蛋白微球的制备工艺及质量进行研究。方法:以白蛋白为载体,采用乳化交联法制备去甲斑蝥素白蛋白微球。在单因素考察的基础上,利用正交设计优化去甲斑蝥素白蛋白微球制备工艺,并对微球的粒径、形态、体外释放特性及稳定性进行研究。结果:制得的微球形态圆整,平均粒径为(0.54±0.13)μm,平均载药量为(51.36±2.45)%,平均包封率为(62.28±3.27)%,体外释放符合Higuchi方程,Q=10.1854t1/2-1.0858(r=0.998 1)。结论:本实验获得了较理想的去甲斑蝥素白蛋白微球,其体外释放特性符合长效制剂特征。     

125I标记外泌体在Pan02胰腺癌荷瘤小鼠体内的生物分布研究

目的 旨在开发用 ¹²⁵I-NaI标记外泌体的方法,并通过 γ 计数仪考察其在 Pan02 胰腺癌荷瘤小鼠体内的生物分布特征。方法 通过非放射性 NaI对用于治疗胰腺癌的工程化外泌体进行冷标记,采用透射电子显微镜、纳米粒子跟踪分析和Western blotting实验对标记前后外泌体进行表征。在此基础上采用Iodogen法进行外泌体的放射性 ¹²⁵I-NaI标记,分离纯化后测定 ¹²⁵I-NaI的标记率,Radio-HPLC法测定给药前后 ¹²⁵I-外泌体的放化纯度以考察其稳定性;将 ¹²⁵I-外泌体单次尾iv于Pan02胰腺癌荷瘤小鼠体内,分别于给药后2、6、24、72 h（每个时间点雌雄各3只）经CO₂麻醉后心脏放血处死小鼠,取血清、主要组织器官及肿瘤,γ计数仪测量其放射性计数,计算各组织/血清在不同时间点的蛋白沉淀率;并计算在不同时间点的每克组织（或每毫升血清）放射性计数占总注入放射性计数的百分比（%ID·g^-1或%ID·mL^-1）。结果 外泌体表征的结果显示,标记前后的外泌体形态一致,均成圆形或茶托样结构;标记前外泌体粒径峰值为 113 nm,标记后外泌体粒径峰值为 122 nm,粒径大小主要分布在 50～200 nm;均表达其标志性蛋白 CD63及 TSG101,符合外泌体特征。¹²⁵I-NaI标记外泌体的标记率为 27.82%,纯化后 HPLC法测得即时放化纯度为 100%,给药后放化纯度为（93.34±5.48）%。在小鼠尾 iv给药后 2 h,标记的外泌体主要分布在肝脏［（10.899 2±1.518 1）%ID·g^-1］和脾脏［（2.566 4±0.799 8）%ID·g^-1］,肿瘤中为［（0.291 0±0.056 0）%ID·g^-1］,脑、心脏、脂肪和肌肉组织摄取较少;给药后72 h,肝脏中仍有较高摄取,肿瘤中仍有放射性分布。给药后 2～6 h各组织脏器的蛋白沉淀率较低,表明 ¹²⁵I-NaI标记外泌体稳定性有所降低。结论 外泌体可以进行 ¹²⁵I标记,而且标记同位素前后对外泌体物理形态、生物学活性无明显影响;¹²⁵I标记外泌体的方法简便,标记率和放化纯度均较高;该外泌体产品在荷瘤小鼠体内大部分血流丰富的组织器官均有分布,且具有一定的肿瘤靶向定位能力。     

心脏靶向超声造影剂空气白蛋白微球的研究(1)

按正交设计筛选了用发射超声能量合成白蛋白空气微球的较佳制备工艺,并对微球的形态、粒径与粒径分布、稳定性、安全性和显影效果进行了系统研究。结果表明：微球的平均直径为 ４．２±０． ２ μｍ,平均浓度为（３．５±１．２）×１０８／ｍｌ。９２．５％的微球直径小于１０μｍ,微球在２℃～５℃条件下能稳定储存１２个月,经兔外用静脉注射后能顺利通过肺微循环到达左心室致使左心室靶向超声显影。     

Transfection by Polyethyleneimine-Coated Microspheres

Polyethyleneimine (PEI) can be used as a DNA delivery mechanism in cell culture and in vivo. Cells can be transfected by using surface-bound PEI, as well as by PEI/DNA microparticles. In the present experiments we extended these observations by preparing microspheres with covalently attached PEI. Blends of poly(?-CBZ-L-lysine) mixed with poly(D,L-lactic-co-glycolic acid) were formed into microspheres using a double-emulsification/solvent evaporation procedure. CBZ (carbobenzoxy) groups on the surface of microspheres were removed by Li⁰/liquid ammonia reduction. Surface amino groups were used for covalent attachment of PEI and other molecules. Silica microspheres with bonded-phase PEI were also used. Microspheres were mixed with plasmid DNA encoding green fluorescent protein and added to cultured cells. PEI-coated microspheres transfected cultured Caco cells and MH-S alveolar macrophages. Expression of the transfected DNA increased over several days. MH-S cells phagocytosed PEI-coated silica microspheres, which were shown to reside in an acidic subcellular compartment. This was demonstrated by conjugating a pH-sensitive fluorescent dye (seminaphthofluorescein, SNAFL) to the microsphere surface. Transfection of MH-S cells was increased when plasmid DNA was complexed with histone on the surface of the microspheres. Conclusions PEI-coated microspheres have potential as a DNA delivery device with advantages of the unique properties of PEI and ease of surface chemical modification.     

Oral delivery of gastro-resistant microencapsulated typhoid vaccine

Oral vaccination has long been regarded as the best alternative to conventional parenteral vaccination considering practical, economical, and immunological aspects. The purpose of this study was to develop albumin–chitosan mixed matrix microsphere-filled coated capsule formulations of Typhoid Vi^® antigen and to determine whether it can induce antigen-specific mucosal and systemic immune responses on oral administration. Formulations with Typhoid Vi^® antigen were prepared and filled into hard gelatin capsules (size # 9) and enteric coated. Formulations were characterized and administered to Sprague–Dawley rats to evaluate the induction of immune response to the antigen. The results indicated that the particle size, zeta potential, swelling, and disintegration rates were optimal for the oral delivery of microencapsulated vaccines. In vivo studies displayed multifold increase of antigen-specific IgG and IgA levels 8 weeks after oral immunization. No statistically significant difference in the antigen-specific IgG and IgA levels were found between oral and parenteral injection groups 8 weeks after vaccination. On the basis of the results of the study, it can be concluded that the oral administration of Typhoid Vi antigen microspheres was successful in inducing antigen-specific systemic and mucosal immune response.     

Preparation and evaluation of alginate-chitosan microspheres for oral delivery of insulin

The alginate-chitosan microspheres with narrow size distribution were prepared by membrane emulsification technique in combination with ion (Ca²⁺) and polymer (chitosan) solidification. The preparation procedure was observed, and the physical properties (particle size distribution, surface morphology, chitosan distribution, zeta potential) of the microspheres were characterized. Subsequently, the microspheres were employed to load model peptide of insulin. The effect of loading ways on the loading efficiency and immunological activity of insulin were investigated. It was shown that the higher loading efficiency (56.7%) and remarkable activity maintenance (99.4%) were obtained when the insulin was loaded during the chitosan solidification process (Method B). Afterward, the release profile in vitro for the optimal insulin-loaded microspheres was investigated. Under the pH conditions of gastrointestinal environment, only 32% of insulin released during the simulated transit time of drug (2 h in the stomach and 4 h in the intestinal). While under the pH condition of blood environment, insulin release was stable and sustained for a long time (14 days). Furthermore, the chemical stability of insulin released from the microspheres was well preserved after they were treated with the simulated gastric fluid containing pepsin for 2 h. Finally, the blood glucose level of diabetic rats could be effectively reduced and stably kept for a long time (∼60 h) after oral administration of the insulin-loaded alginate-chitosan microspheres. Therefore, the alginate-chitosan microspheres were found to be promising vectors showing a good efficiency in oral administration of protein or peptide drugs.     

Formulation and characterization of albumin microspheres containing norcantharidate for liver tumor targeting

Abstract

The objectives of this study were first to encapsulate norcantharidate into albumin microspheres by the emulsion crosslinking method and second to characterize the microspheres in terms of the morphological examination, particle size, and encapsulation efficiency. The in vitro release of norcantharidate from the microspheres was studied by using the dialysis bag method. Pharmacokinetics and biodistribution studies were used to evaluate the advantages of microspheres than the conventional formulations. The microspheres prepared by crosslink emulsion were with uniform size, smooth surface, spherical shape, and disperse evenly. The particle size was uniform (13.3?±?0.4?µm) and the encapsulation efficiency was 54.3?±?4.18%. In vitro release indicated that the norcantharidate microspheres had a well-sustained release efficacy and fitted Korsmeyer’s Peppas release model. In vivo studies showed that pharmacokinetics of norcantharidate microspheres could be described by the model of two-compartment after i.v. administration and had higher AUC inside liver and spleen than the injection group. No histological change occurred to the rat liver after the administration of norcantharidate microspheres.     

Pharmacokinetics,tissue distribution and excretion of porcine fibrinogen after intraperitoneal injection of a porcine-derived fibrin glue to rats

The aim of the present study was to characterize the preclinical pharmacokinetics, tissue distribution and excretion profiles of porcine fibrinogen in rats after intraperitoneal injection of a porcine-derived fibrin glue. A sensitive and rapid isotope-labeled assay method was developed and validated for quantitative analysis in biological analysis. Porcine fibrinogen, the major composition of the fibrin glue, was radioiodinated with Na¹²⁵I using the Iodo-Gen method. Following the purification and identification of ¹²⁵I-porcine fibrinogen, the fibrin glue containing ¹²⁵I-porcine fibrinogen was intraperitoneally administered to rats at three single dosages (100, 200, 400 mg/kg of porcine fibrinogen). The results showed that the ¹²⁵I-labeled assay method was suitable for the quantification of porcine fibrinogen in plasma samples, tissue samples and excreta samples with satisfactory linear (r² > 0.998), precision (<13%), accuracy (95.9–104.2%) and recovery (>85%). After three single administrations, plasma concentration profiles showed a slow absorption phase with the mean t_max of 1.83–5.67 h and a slow elimination proceeding with the terminal elimination half-life (T_1/2) of 84.5–96.3 h. Porcine fibrinogen was widely distributed to most of the tissues examined after a single intraperitoneal administration at 200 mg/kg to rats. The radioactive porcine fibrinogen showed substantial disposition in liver, kidneys, stomach and intestine. Approximately 79.3% and 17.2% of administered radioactivity were recovered in urine and feces within 528 h post-dosing, which indicated the major elimination route was urinary excretion.