肺靶向地塞米松微球的制备及体外释药

目的:研究水溶性药物地塞米松磷酸钠肺靶向微球制备工艺的优化。方法:以油/水型乳化-溶剂挥发法制备微球,考察微球的性质及肺靶向性。维持其他条件不变,内相中加入甲醇和改变外相中氯化钠的加入量后,考察微球的载药量变化。结果:所制的微球的平均粒径为(8.37±4.0)μm。突释性好,最初0.5h释药量达48.28%。各器官石蜡切片中,肺组织中有较多微球嵌顿。随着内相中加入甲醇和外相中加入氯化钠,微球载药量提高。结论:地塞米松微球有良好的肺靶向性。采用油/水型乳化-溶剂挥发法制备水溶性地塞米松微球时,内相中加入甲醇和外相中加入氯化钠有助于提高微球的载药量。     

紫杉醇PLGA微球制备及体外性质评估

目的：以乳酸-羟基乙酸共聚物（PLGA）为材料,制备用于肿瘤内注射的紫杉醇PLGA长效缓释微球.方法：采用改良溶剂蒸发法制备,对微球的体外性质以及不同剂量（10,15,25 kGy）60Coγ射线对微球性质的影响进行考察.结果：制得的微球形态圆整,载药量、包封率、平均粒径和跨距分别为1.53%,97.29%,42.72μm和0.95.药物体外释放30 d累计释放达到56.19%,体外降解30 d后微球失去完整结构,表面粗糙.3个剂量60Coγ射线的灭菌效果均良好,且对微球的体外性质均无明显影响.微球中二氯甲烷的残留量低于药典规定的限度.结论：紫舷杉醇PLGA微球满足缓释长效的要求,对恶性肿瘤的间质化疗具有一定前景.     

紫杉醇壳聚糖肺靶向微球的制备

目的研制具有肺靶向性的紫杉醇壳聚糖微球,并对处方工艺进行优化。方法以壳聚糖为载体,采用乳化一化学交联法制备紫杉醇壳聚糖微球。单因素试验考察了油／水体积比、紫杉醇浓度、乳化时间、乳化剂量等因素,采用正交设计优化微球制备工艺,以HPLC法测定微球载药量、包封率。结果制得的微球显微观察形态圆整、表面光滑,无黏连;平均粒径为（8．23±0．25）μm,粒径在7～12μm平均占微球总数的84．2％,载药量为16．20％±1．15％,包封率为81．29％±1．62％。结论筛选的最佳处方工艺制备的微球粒径大小适宜,可满足肺靶向微球的要求并免除过敏试剂的加入。     

肺靶向多西紫杉醇壳聚糖微球的制备与工艺优化

目的：研制肺靶向多西紫杉醇壳聚糖微球,并对处方工艺进行筛选。方法：以壳聚糖为载体,采用乳化-化学交联法制备多西紫杉醇壳聚糖微球。在单因素考察的基础上,利用正交试验设计优化微球制备工艺,采用HPLC法测定微球的载药量与包封产率。结果：制得的微球显微观察形态圆整、表面光滑,无粘连;平均粒径为（8．63±0．27）μm,粒径7—12μm的微球平均占总数的83．5％,载药量为（25．01±1．80）％,包封产率为（85．54±2．21）％。结论：筛选的最佳处方工艺制备的微球粒径大小适宜,可满足肺靶向微球的要求;该制剂有可能成为临床肺部肿瘤治疗的一种靶向制剂。     

关节腔注射用甲氨蝶呤缓释微球的制备及体内外释药研究*

目的:制备一种可用于关节腔注射的甲氨蝶呤(methotrexate,MTX)聚乳酸-聚羟基乙酸共聚物(PLGA)缓释微球,并研究其体内外释药规律.方法:应用O/W溶剂挥发法制备MTX-PLGA微球,对其表面形态、粒径分布进行表征并测定其包封率、载药量和体内外释药谱;采用HPLC法分析药物含量;体内释放采用大鼠皮下气囊模型.结果:微球表面光滑圆整,平均粒径为(38.47±1.32)μm,包封率和载药量分别为(62.71±0.84)%和(3.23±0.13)%.体外释放t50为20 d,体外释放速率常数Kr=0.038μg·mL-1·d-1.体内试验显示,在气囊中的释放速率常数KR=0.12μg·mL-1·d-1.结论:采用本法制备的MTX-PLGA微球具有明显的缓释作用,有望成为一种有效的治疗类风湿关节炎的制剂.     

可生物降解的聚乳酸-羟基乙酸共聚微球制备与性能研究进展

生物可降解材料乳酸-羟基乙酸共聚物(PLGA)有良好的生物相容性和安全性,在体内降解为二氧化碳和水.由于PLGA易于合成、质量稳定,具有生物兼容性、生物可降解性、机械强度、降解速度可调节性和良好的可塑性,自2000年后被大量用作微球控释系统的载体材料.     

异烟肼肺靶向性微球的制备及其小鼠体内分布

目的：制备异烟肼肺靶向性微球,评价其体外释药特性及在动物体内的肺靶向性。方法：采用溶剂挥发法制备微球,动态透析法考察其体外释药性能,实验动物静脉注射后测定其各组织的药物浓度,研究其体内相对分布百分率及肺靶向性。结果：制得的微球粒径在7～30μm的占微球总数的88．8％,平均粒径为（16.7±4．6）μm,包封率为86．92％,载药量为（40．7±3.6）％（n=5）,体外释药T50为68min,轻对照组延长了4.5倍。动物实验表明,制得微球后,药物在肺内的相对分布百分率明显高于其它组织与血液,并轻对照组提高了4倍。结论：本法制得的异烟肼微球具有明显的缓释性及肺靶向性。     

两种方法制备肺靶向地塞米松磷酸钠微球的比较

目的:研究两种制备方法所制备的肺靶向地塞米松磷酸钠微球的特性,确定两种方法是否适合用于制备该微球。方法:对油／水型乳化-溶剂挥发法的工艺进行优化,以优化后的油／水型乳化-溶剂挥发法和水／油／水型乳化-溶剂挥发法制备微球,考察微球的大小、载药量、体外释药等性质。结果:两法所制的微球的平均粒径相近,载药量和体外释药特性各不相同。结论:两种方法都适合用于制备肺靶向的地塞米松微球。从载药量方面分析,优化后的油／水型乳化-溶剂挥发法较好。     

不同封端的PLGA/PLA-醋酸曲普瑞林微球的制备及体内外评价

目的考察微球载体材料聚乳酸-羟基乙酸共聚物(poly-lactic-co-glycolic acid,PLGA)和聚乳酸(poly(D,L-lactide acid),PLA)的不同封端基团对于包载醋酸曲普瑞林(triptorelin acetate,TA)微球的形态、粒径、包封率、体外释放行为以及体内药效学的影响。方法使用复乳化-溶剂挥发法制备包载TA的PLGA和PLA微球;用扫描电镜观察微球的形态,用激光粒度测定仪测定微球的粒径;建立高效液相色谱法(HPLC)用于TA包封率及体外释放度的测定;采用酶联-免疫吸附法考察了微球经肌肉注射后对正常雄性Sprague Dawley大鼠血浆睾酮浓度的影响。结果制备得到的微球形态为球形或类球形,平均粒径约为30μm。PLGA和PLA,尤其是PLGA,其分子末端基团对TA的包封率和体外释放速率均有影响。酯封端的PLGA微球的包封率显著高于酸封端的微球,而酯封端的释放速度要慢于酸封端。体内药效学实验结果显示,大鼠体内睾酮水平在注射微球后两个小时达到峰值,之后逐渐下降,不同微球之间无显著性差异。结论不同封端结尾的PLGA和PLA对微球形态、包封率和体外释药速率有显著影响,但对正常大鼠体内睾酮水平的影响没有显著性差异。     

肺靶向利福平聚乳酸微球的研究

在单因素考察的基础上进行正交试验设计,筛选出肺靶向利福平聚乳酸微球的最佳制备工艺条件;利用桨板法研究了微球的体外释药规律;考察了微球在不同温度下的稳定性;用新西兰兔为实验对象,研究了利福平聚乳酸微球的体内药动学及组织药物分布。结果制得的微球形态圆整,粒径在5～15μm范围内的占总体积的86.54%,微球平均粒径为9.00±4.08μm;包封率为31.9%;载药量为16.0%;体外释药方程为Q=20.77+10.12T_1/2(γ=0.9892);微球在冰箱4℃和室温(20～25℃)条件下性质稳定;体内实验表明微球具有长效和肺靶向双重作用。     

Sophoridine-loaded PLGA microspheres for lung targeting: preparation,in vitro,and in vivo evaluation

Lung-targeting sophoridine-loaded poly(lactide-co-glycolide) (PLGA) microspheres were constructed by a simple oil-in-oil emulsion-solvent evaporation method. The obtained microspheres were systematically studied on their morphology, size distribution, drug loading, encapsulation efficiency, in vitro release profile, and biodistribution in rats. The drug-loaded microparticles showed as tiny spheres under SEM and had an average size of 17?μm with 90% of the microspheres ranging from 12 to 24?μm. The drug loading and encapsulation efficiency were 65% and 6.5%, respectively. The in vitro drug release behavior of microspheres exhibited an initial burst of 16.6% at 4?h and a sustained-release period of 14 days. Drug concentration in lung tissue of rats was 220.10?μg/g for microspheres and 6.77?μg/g for solution after intraveneous injection for 30?min, respectively. And the microsphere formulation showed a significantly higher drug level in lung tissue than in other major organs and blood samples for 12 days. These results demonstrated that the obtained PLGA microspheres could potentially improve the treatment efficacy of sophoridine against lung cancer.     

In vitro and in vivo evaluation of actively targetable nanoparticles for paclitaxel delivery

The aim of the present work was to assess the merits of an actively targetable nanoparticles (ATN), PEG-coated biodegradable polycyanoacrylate nanoparticles (PEG-nanoparticles) conjugated to transferrin, for paclitaxel delivery. PEG-nanoparticles loading paclitaxel were prepared by solvent evaporation technique in advance. ATN were prepared by coupling of transferrin to PEG-nanoparticles. The results showed that the average encapsulation efficiency of ATN was 93.4+/-3.6% with particle size (101.4+/-7.2 nm) and zeta-potential (-13.6+/-1.1 mV). The paclitaxel loaded ATN exhibited a low burst effect with about only 16.2% drug release within the first phase. Subsequently, paclitaxel release profiles displayed a sustained release phase. The amount of cumulated paclitaxel release over 30 days was 81.6%. ATN exhibited a markedly delayed blood clearance in mice, and the paclitaxel level from ATN remained much higher at 24 h compared with that of free drug from paclitaxel injection. The distribution profiles of ATN in S-180 solid tumor-bearing mice after intravenous administration showed the tumor accumulation of paclitaxel increase with time, and the paclitaxel concentration in tumor was about 4.8 and 2.1 times higher than those from paclitaxel injection and PEG-nanoparticles at 6 h after intravenous injection. For mice treated with 20 mg/kg x 5 of ATN, the decrease in body weight was limited within 4% of the initial weight at 5 days after the final administration, and tumor regression was significantly observed with complete tumor regression for five out of nine mice. The tumor burden with ATN-treated mice was much smaller compared with free paclitaxel or NTN-treated mice. In addition, the life span of tumor-bearing mice was significantly increased when they were treated with ATN, in particular, three mice survived over 60 days. Thus, PEG-coated biodegradable polycyanoacrylate nanoparticles conjugated to transferrin could be an effective carrier for paclitaxel delivery.     

Preparation and the in-vivo evaluation of paclitaxel liposomes for lung targeting delivery in dogs

Objectives The aim of this study was to develop paclitaxel liposomes for a lung targeting delivery system. Methods The liposomes composed of Tween‐80/HSPC/cholesterol (0.03 : 3.84 : 3.84, mol/mol), containing paclitaxel and lipids (1 : 40, mol/mol), were prepared by a combination of solid dispersion and effervescent techniques, and then subjected to ultrasonication. The pharmacokinetics and biodistribution of liposomal and injectable formulation of paclitaxel in dogs were studied after intravenous administration. Key findings The mean diameter, polydispersity index, zeta‐potential and entrapment efficiency of the liposomes were 501.60 ± 15.43 nm, 0.28 ± 0.02, ?20.93 ± 0.06 mV and 95.17 ± 0.32%, respectively. The liposomal formulation kept stable for at least 3 months at 6 ± 2°C and didn't cause haemolysis. The liposome carrier decreased the area under the curve and terminal half‐life of paclitaxel compared with paclitaxel injection ranging from 0.352 ± 0.031 mg/l*h and 0.0671 ± 0.144 h to 0.748 ± 0.062 mg/l*h and 1.978 ± 0.518 h, respectively. The paclitaxel liposomes produced a drug concentration in the lung that was markedly higher than that in other organs or tissues and was about 15‐fold of that of paclitaxel injection at 2 h. Conclusions To sum up, these results demonstrated that the paclitaxel liposomes are an effective lung targeted carrier in the treatment of lung cancer.     

均匀设计法优化汉防己甲素肺靶向微球的处方及制备工艺

目的：制备肺部靶向的聚乳酸汉防己甲素微球。方法：采用液中干燥法制备聚乳酸汉防己甲素微球，按均匀设计法，对实验结果进行多元逐步回归优化实验条件，筛选汉防己甲素微球的最佳制备工艺。结果：所制备微球粒径在7～15μm者占80．3％，包封率为61．7％，载药量为46．9％。结论：用优化均匀设计优化后的制备工艺制取TET-PLA微球是可行的。     

微球的制备和表征

目的制备葡激酶突变体(K35R，DGR)的聚乳酸-羟基乙酸(PLGA)微球，使其在包封和释放过程中都能保持活性。方法使用复乳溶剂挥发法制备DGR的PLGA微球，研究了搅拌速度、PLGA浓度、内水相和外水相中的添加剂对蛋白包封率以及微球性质的影响，并进行了DGR微球的体外和体内释放试验。结果2%聚乙烯醇可以有效抑制超声乳化时DGR在水/二氯甲烷界面上的变性，将DGR的活性回收率从16%提高到几乎100%。在外水相中加入NaCl可以显著提高蛋白包封率，同时对微球的粒径分布和表面形态也产生了重要影响。DGR微球的体外释放呈现两个时相，15 d释放大约DGR总活性的50%。DGR微球在体内持续释放5 d。结论制备的PLGA微球，DGR包封率高，稳定性较好，是DGR的良好载药系统。     

Preparation and testing of cefquinome-loaded poly lactic-co-glycolic acid microspheres for lung targeting

The aim of this study was to prepare cefquinome-loaded poly lactic-co-glycolic acid (PLGA) microspheres and to evaluate their in vitro and in vivo characteristics. Microspheres were prepared using a spry drier and were characterized in terms of morphology, size, drug-loading coefficient, encapsulation ratio and in vitro release. The prepared microspheres were spherical with smooth surfaces and uniform size (12.4?±?1.2?μm). The encapsulation efficiency and drug loading of cefquinome was 91.6?±?2.6 and 18.3?±?1.3%, respectively. In vitro release of cefquinome from the microspheres was sustained for 36?h. In vivo studies identified the lung as the target tissue and the region of maximum cefquinome release. A partial lung inflammation was observed but disappeared spontaneously as the microspheres were removed through in vivo decay. The sustained cefquinome release from the microspheres revealed its applicability as a drug delivery system that minimized exposure to healthy tissues while increasing the accumulation of therapeutic drug at the target site. These results indicated that the spray-drying method of loading cefquinome into PLGA microspheres is a straightforward method for lung targeting in animals.     

Formulation and in vitro/in vivo evaluation of terbutaline sulphate incorporated in PLGA (25/75) and L-PLA microspheres

Terbutaline sulphate (TBS) is widely used in the treatment of bronchial asthma, chronic bronchitis and emphysema. Because of its short biological half life and dosing schedule, a long acting TBS formulation is required to improve patient compliance. The objective of this study was to develop a TBS containing biodegradable microsphere formulation. Poly(D, L-lactide-co-glyco-lide) (PLGA) and poly(L-lactic acid) (L-PLA) were chosen as matrix materials. A solvent evaporation method was used for preparation of microspheres. Surface morphology, particle size distribution and encapsulation efficiency were investigated. In vitro release studies were performed in pH 7.4 phosphate buffer. In vivo distribution of microspheres were studied in the Swiss albino male mice. All microspheres were spherical in shape and had a porous surface with mean diameters of 9–21 μm. The encapsulation efficiency was influenced by the polymer type, but not the molecular weight. About 90% of the initial amount was trapped in PLGA microspheres, and the remainder was on the surface. In the case of L-PLA, 50% of the total drug was associated with the surface of microspheres. The in vitro release pattern was biphasic characterized by an initial burst phase followed by a slower phase. The L-PLA microspheres released ～92% of the initial payload in 72 h. On the other hand, TBS release was increased with an increase in the molecular weight of PLGA. Biodistribution of L-PLA microspheres was characterized by an initially high uptake (35%) by the lungs. All these results suggest that L-PLA and PLGA microspheres have the potential to be used for passive lung targeting.     

Effects of formulation factors on encapsulation efficiency and release behaviour in vitro of huperzine A-PLGA microspheres

To develop a long-acting injectable huperzine A-PLGA microsphere for the chronic therapy of Alzheimer's disease, the microsphere was prepared by using an o/w emulsion solvent extraction evaporation method based on a series of formulation design of the emulsion. The dialysis method was used for release analysis. The encapsulation efficiency and release amount of the microspheres were determined by a UV/VIS spectrophotometer. The morphology of the microspheres was observed by scanning electron microscopy. The distribution of the drug within microspheres was observed by a confocal laser scanning microscope. The results indicated that the PLGA 15?000 microspheres possessed a smooth and round appearance with average particle size of 50?µm or so. The encapsulation percentages of microspheres prepared from PLGA 15?000, 20?000 and 30?000 were 62.75%, 27.52% and 16.63%, respectively. The drug release percentage during the first day decreased from 22.52% of PLGA 30?000 microspheres to 3.97% of PLGA 15?000 microspheres, the complete release could be prolonged to 3 weeks. The initial burst release of microspheres with higher molecular weight PLGA could be explained by the inhomogeneous distribution of drug within microspheres. The encapsulation efficiency of the microspheres improved as the polymer concentration increased in the oil phase and PVA concentration decreased in the aqueous phase. The burst release could be controlled by reducing the polymer concentration. Evaporation temperature had a large effect on the drug release profiles. It had better be controlled under 30°C. Within a certain range of particle size, encapsulation efficiency decreased and drug release rate increased with the reducing of the particle size.