雌二醇聚乳酸类微囊的制备与体外评价

目的　以聚乳酸或乳酸 乙醇酸共聚物为载体材料制备雌二醇缓释微囊。方法　实验中采用乳化 溶剂萃取法制备微囊 ,考察了影响微囊特性以及体外释药的各种因素 ,采用单因素试验方差分析进行因素影响的显著性检验 ,并在此基础上采用T方法进行两两间多重比较 ,进一步考察因素各水平间差异的显著性。结果　结果表明 ,粒径和加水萃取速度对雌二醇微囊的包封率有显著性影响 (P <0 0 1) ;随油相载体的浓度以及加水萃取速度对微囊的粒径影响显著 (P <0 0 1)。体外释药研究表明 ,加水萃取速度和载体的型号和分子量对微囊释药影响显著 (P <0 0 1)。但这些影响因素的各水平之间的差异性并不都具有显著性。结论　通过改变处方以及制备工艺可以得到具有不同性质的雌二醇聚乳酸类缓释微囊     

盐酸多西环素注入用缓释凝胶的体外释放度研究

目的：考察盐酸多西环素注入用缓释凝胶的体外释放特性及机制;方法：考察聚乳酸(PLA)和聚乳酸-羟基乙酸共聚物(PLGA)型号、聚合物浓度、含药量、释放介质和释放装置对药物释放的影响,制定出盐酸多西环素注入用缓释凝胶的体外释放试验方案并进行体外释放度测定;结果：凝胶中药物在水中的释放分为2个阶段：第1个阶段为“突释”,第2个阶段符合Higuichi方程。结论：所定方法可用于盐酸多西环素注入用缓释凝胶的体外释放试验。     

尼索地平微球的制备

采用溶剂挥发法制备了尼索地平微球 ,考察了制备工艺中影响微球质量的 5个主要因素 ,筛选出较理想的处方和工艺。所得微球形态圆整 ,表面光滑 ,粒径 (18.2± 3.8) μm,载药量 2 1.2 % ,包封率 85 .4 %。     

Box-Behnken设计-效应面法优化延胡索乙素聚乳酸-羟基乙酸共聚物纳米粒处方和体外释药行为研究

目的 Box-Behnken设计-效应面法（Box-Behnken design-response surface method,BBD-RSM）优化延胡索乙素（THP）聚乳酸-羟基乙酸共聚物[poly（lactic-co-glycolic acid）,PLGA]纳米粒（THP-PLGA-NPs）处方,并进行体外评价。方法 纳米沉淀法制备THP-PLGA-NPs,以包封率、载药量、多分散系数（polydispersity index,PDI）和粒径大小为评价指标,单因素结合BBD-RSM筛选最优处方,采用甘露醇作为冻干保护剂制备成冻干粉,将最优处方进行表征及体外释放实验。结果 最佳处方为PLGA用量为491.8 mg、油水体积比1：5.2、乳化剂质量分数为1.12%。THP-PLGA-NPS包封率为（185.07±1.06）%,载药量为（4.73±0.21）%,粒径为（181.32±7.14）nm,分别与模型预测值接近。体外释药具有明显的缓释特征,释药过程符合Higuchi模型：M_t/M_∞=0.112 4 t^1/2+0.078 0,r=0.987 9。结论 Box-Behnken实验设计可用于THP-PLGA-NPS处方的筛选,且优化后的纳米粒具有缓释作用。     

Development of a single-dose recombinant CAMP factor entrapping poly(lactide-co-glycolide) microspheres-based vaccine against Streptococcus agalactiae

Streptococcus agalactiae is an important contagious bovine mastitis pathogen. Although it is well controlled and even eradicated in most Northern European and North American dairy herds, the prevalence of this pathogen remains very high in China. However, research on development of a vaccine against S. agalactiae mastitis is scarce. The aims of the present study were to: (1) develop a single-dose vaccine against S. agalactiae based on poly(lactic-co-glycolic acid) (PLGA) microspheres (MS) encapsulated CAMP factor, a conserved virulent protein encoded by S. agalactiae’s cfb gene; and (2) evaluate its immunogenicity and protective efficacy in a mouse model. The cfb gene was cloned and expressed in a recombinant Escherichia coli strain Trans1-T1. The CAMP factor was tested to determine a safe dose range and then encapsulated in MS of PLGA (50:50) to assess its release pattern in vitro and immune reaction in vivo. Furthermore, a mouse model and a histopathological assay were developed to evaluate bacterial burden and vaccine efficacy. In the low dosage range (<100 μg), CAMP factor had no obvious toxicity in mice. The release pattern in vitro was characterized by an initial burst release (44%), followed by a sustained and slower release over 7 wk. In mice immunized with either pure CAMP factor protein or PLGA-CAMP, increased antibody titers were detected in the first 2 wk, whereas only PLGA-CAMP immunization induced a sustained increase of antibody titers. In mice vaccinated with PLGA-CAMP, mortality and bacteria counts were lower (compared to a control group) after S. agalactiae challenge. Additionally, no pathological lesions were detected in the vaccinated group. Therefore, PLGA-CAMP conferred protective efficacy against S. agalactiae in our mouse model, indicating its potential as a vaccine against S. agalactiae mastitis. Furthermore, the slow-release kinetics of PLGA MS warranted optimism for development of a single-dose vaccine.     

Bioerodable Ketamine-Loaded Microparticles Fabricated Using Dissolvable Hydrogel Template Technology

For severe cancer-related pain that is not relieved adequately by escalating doses of oral or parenterally administered strong opioid analgesics such as morphine, alone or in combination with an adjuvant drug such as ketamine, more invasive dosing routes may be warranted. One such approach involves surgical implantation of an intrathecal pump to deliver small doses of analgesic or adjuvant drugs in close proximity to the receptors that transduce their pain-relieving effects. However, the use of implanted devices is associated with a range of catheter-related problems. To address this, we have developed biodegradable microparticles loaded with the analgesic adjuvant drug, ketamine, for sustained release after a single bolus intrathecal injection. Drug-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles were prepared using a dissolvable hydrogel template. Using PLGA with 3 different ratios of lactic acid to glycolic acid (L/G), relatively high ketamine loading and homogenous particle shape and size were achieved. Specifically, ketamine loading of PLGA5050, PLGA7525, and PLGA8515 in ester-terminated microparticles was 20.0%, 20.4%, and 18.9%, respectively. The microparticles were within the desired size range (20 μm diameter and 30 μm height) and in vitro release was sustained for ≥14 days with an acceptable initial burst release (～10%-20%) achieved.     

葫芦素B-聚乳酸-羟基乙酸共聚物载药纳米粒的构建与药效学评价

目的 以聚乳酸-羟基乙酸共聚物（PLGA）作为纳米制剂载体材料将葫芦素B制备成纳米粒,并考察其对HepG2肝癌细胞的抑制效果。方法 使用乳化溶剂蒸发法制备葫芦素B-PLGA载药纳米粒,以PLGA浓度（X₁）、PVA浓度（X₂）和药物浓度（X₃）作为考察因素,以载药纳米粒的粒径大小（Y₁）和包封率（Y₂）作为评价指标,应用中心复合设计-效应面法优化葫芦素B-PLGA载药纳米粒处方;测定了纳米粒的粒径分布和Zeta电位值,通过透射电镜观察其微观形态,并考察了葫芦素B-PLGA载药纳米粒的体外药物释放特性;比较了葫芦素B与葫芦素B-PLGA载药纳米粒对HepG2肝癌细胞的抑制效果。结果 葫芦素B-PLGA载药纳米粒的最优处方组成为：PLGA浓度为9.0%,PVA浓度为2.0%,药物浓度为4.5%,制备的纳米粒粒径为（145.4±15.8） nm,Zeta电位值为（-7.6±0.8） mV;透射电镜下可观察到纳米粒表面光滑,分布均匀;葫芦素B-PLGA载药纳米粒释药前期出现突释,后期平缓,48 h药物释放达到86%;葫芦素B-PLGA载药纳米粒对HepG2肝癌细胞的抑制作用显著高于葫芦素B。结论 葫芦素B-PLGA载药纳米粒可延缓药物释放,提高对HepG2肝癌细胞的抑制活性,为进一步临床研究奠定实验基础。     

PEG–lipid–PLGA hybrid nanoparticles loaded with berberine–phospholipid complex to facilitate the oral delivery efficiency

The natural product berberine (BBR), present in various plants, arouses great interests because of its numerous pharmacological effects. However, the further development and application of BBR had been hampered by its poor oral bioavailability. In this work, we report on polymer–lipid hybrid nanoparticles (PEG–lipid–PLGA NPs) loaded with BBR phospholipid complex using a solvent evaporation method for enhancing the oral BBR efficiency. The advantage of this new drug delivery system is that the BBR–soybean phosphatidylcholine complex (BBR–SPC) could be used to enhance the liposolubility of BBR and improve the affinity with the biodegradable polymer to increase the drug-loading capacity and controlled/sustained release. The entrapment efficiency of the PEG–lipid–PLGA NPs/BBR–SPC was observed to approach approximately 89% which is more than 2.4 times compared with that of the PEG–lipid–PLGA NPs/BBR. To the best of our knowledge, this is the first report on using polymer material for effective encapsulation of BBR to improve its oral bioavailability. The prepared BBR delivery systems demonstrated a uniform spherical shape, a well-dispersed core-shell structure and a small particle size (149.6?±?5.1?nm). The crystallographic and thermal analysis has indicated that the BBR dispersed in the PEG–lipid–PLGA NPs matrix is in an amorphous form. More importantly, the enhancement in the oral relative bioavailability of the PEG–lipid–PLGA NPs/BBR–SPC was ～343% compared with that of BBR. These positive results demonstrated that PEG–lipid–PLGA NPs/BBR–SPC may have the potential for facilitating the oral drug delivery of BBR.     

包裹放射性核素131I的高分子纳米药物的制备及其放射自显影实验

目的制备一种包裹放射性核素的纳米药物,并对其理化性质及放射性特征进行研究。方法采用高分子纳米材料聚乳酸/羟基乙酸(PLGA)作为载体,用放射线核素131I作为包裹药物,通过双乳化法和冷冻干燥技术制备包裹131I的PLGA纳米药物。并对其外观、形态及放射性特征进行观察分析,采用光镜、电镜及放射自显影术,检测其粒径、电位及其包裹放射性核素的能力。结果通过本方法成功制备了包裹放射性核素131I的高分子纳米药物;光镜下观察其形态规则、呈球形,大小均匀,平均粒径为(1.55±0.25)μm,电位为(-30.1±5.3)mv;包封率为(1.0±0.5)%;单个PLGA纳米药物的放射性活度约为1.1×10-2 Bq,单个纳米药物的比活度为5.2×10-3 Bq/nm3。体外放射自显影图像显影清晰,与空白对照组对比差异有统计学意义。结论包裹放射性核素131I的纳米放射性微球理化性质稳定,具有较高的包封率,放射性自显影效果好,为对放射性核素抵抗或不敏感的肿瘤核素诊断与治疗提供重要方法和思路,为进一步包裹放射性核素的靶向性纳米药物的研究奠定了基础。