伊维菌素微胶囊的制备及其体外释放的研究

市售伊维菌素制剂存在生物利用度低,释药峰谷浓度差异大等问题,本文以明胶为囊材,采用单凝聚法制备伊维菌素长效注射微胶囊油混悬剂。以微胶囊的粒径、载药量和包封率为制备工艺的优化指标,采用分光光度法测定微胶囊内药物含量及包封率。结果显示：最佳工艺制备的微胶囊的平均包封率为63.2%,载药量为18.3%,微胶囊的正圆度高、表面平滑,粒径分布在20~50 μm,药物呈缓慢持续释放,体外累计释放率18 h为30.0%,44 h后仅为51.0%。伊维菌素微胶囊制剂可大大增加体内留存时间,提高生物利用度,缓释效果显著。     

两种液中干燥法制备盐酸多西环素微囊的比较研究

分别用水中干燥法和油中干燥法制备盐酸多西环素微囊,比较各自制得的微囊质量参数及其体外释药特性,以期为盐酸多西环素缓释制剂提供科学依据.以乙基纤维素为囊材,通过正交设计分别考察各因素对微囊质量的影响,评定微囊的大小、形态、载药量、包封率等质量指标,以释放度实验研究其释药特性.结果显示,水中干燥法所制得微囊粒径20 ～ 30 μm,包封率为87.3％;油中干燥法微囊粒径范围为200～400μm,包封率为93.7％.上述结果表明油中干燥法所得微囊粒径较大,包封率、载药量均明显高于水中干燥法制得的微囊;体外释药实验表明,微囊化大大延缓了盐酸多西环素的释放时间.     

磷酸泰乐菌素脂质体的制备及体外释放动力学研究

为延长磷酸泰乐菌素在体内的作用时间,通过比较采用硫酸铵梯度法制备其脂质体制剂。以包封率为指标,分别考察磷脂与胆固醇之比、药脂比、硫酸铵浓度、孵化温度和孵化时间对包封率的影响,并在此基础上进行正交试验筛选最优处方。同时,对所得脂质体的形态、粒径及分布、包封率及体外释放动力学进行研究。结果显示,正交试验优化得到的最佳处方工艺如下,磷脂与胆固醇质量比为4∶1,药脂比为1∶10,硫酸铵浓度为300 mmol/L,体系pH值为7.0,孵化温度为50℃,孵化时间为20 m in。电镜下观察脂质体呈球形或类球形,分布均匀,平均粒径为6.526μm,且大部分在1μm~12μm之间,包封率为58.32%,体外释药符合W eibull方程(r=0.976 4)。研究证实硫酸铵梯度法制备磷酸泰乐菌素脂质体方法可行,包封率高,稳定性好,体外释药具有一定的缓释效应。     

恩诺沙星聚合物胶束的制备及体外释放

通过比较3种不同质量比的两嵌段共聚物制备的聚合物胶束,优化恩诺沙星聚合物胶束的制备工艺,并考察该胶束的理化性质和体外释药特性。以自乳化溶剂挥发法制备恩诺沙星聚合物胶束,并采用单因素法优化处方;HPLC法测定其载药量、包封率、体外释药特性,激光粒度仪测定其粒径及分布,红外分光光度法（IR）确证含药胶束特征。结果显示,采用PLA16000-mPEG2000（聚乳酸-聚乙二醇单甲醚）共聚物为载体,以丙酮为有机溶剂,所制备胶束平均粒径为（117.2±8.2）nm,载药量为（3.3±0.17）%,包封率为（32.3±1.70）%;相对于另外2种材料制备的胶束有较好的载药量,且IR确证药物已被包封在胶束中。恩诺沙星胶束体外释药试验表明其具有一定的缓释特性。     

黄体酮聚乳酸微球制备及其体外释药特性研究

本试验旨在制备黄体酮聚乳酸微球,并考察其体外释药性能。以包封率、载药量为主要评价指标,考察制备黄体酮微球的主要影响因素,筛选出最佳工艺条件。扫描电子显微镜观察微球形态,紫外—可见分光光度法测定微球的包封率、载药量和体外释药特性。最佳工艺所制备的微球光滑、圆整、均匀、分散性好,包封率为(80.60±1.00)%,载药量为(10.63±0.05)%,在7 d内累积释药率达53.41%。制备微球包封率和载药量高,具有明显的缓释效果,能有效地延长药物作用时间。     

玉屏风多糖脂质体的制备及表征研究

优选玉屏风多糖脂质体的最佳工艺并对其进行表征验证。采用逆向蒸发法制备玉屏风多糖脂质体,以膜材比、脂药比和超声时间为考察因素,包封率为评价指标,采用L9(34)正交试验设计优选制备条件,以超速离心法测定包封率,体外释药试验验证,纳米颗粒分析仪和透射电镜测定其粒径大小与形态。制备玉屏风多糖脂质体的最佳工艺为膜材比8∶1,脂药比4∶1,超声时间90s,包封率88.38%,24h累积释放率73.45%,平均粒径132.65nm。制备的玉屏风多糖脂质体具有较高的包封率与良好的缓释作用,粒径和形态较均匀,重现性好。     

槲皮素纳米粒的制备及其体外评价

为了考察槲皮素纳米粒的体外特性,试验采用薄膜分散法制备了槲皮素纳米粒,采用透射电镜、X射线衍射法(XRD)对其进行表征,采用动态膜透析法考察载药纳米粒的体外释药特性。结果表明:薄膜分散法制备的纳米粒呈球形或类球形,平均粒径为(51.5±5.9)nm,平均包封率为(89.13±3.97)%,平均载药量为(2.87±1.91)%;槲皮素以无定型状态或分子状态分散在纳米粒中;槲皮素纳米粒体外释放具有明显的缓释作用。说明槲皮素纳米粒制备工艺简单,其粒径、包封率、载药量可控,具有缓释作用。     

尿素微胶囊的缓释性能试验

本文以生物可降解的海藻酸钠一氯化钙(NaAlg-CaCl2)为骨架材料,用高压静电法,对尿素进行微囊化并进行缓释性能研究.结果表明:本方法制备的尿素微胶囊不但形状圆整、粒径分布均匀,而且有较高的包封率,加入少量壳聚(chitosan,CS)可较大程度地提高尿素的包封率.采用NaAlg-CaCl2作为壁材,以高压静电法对尿素进行微胶囊化是可行的.     

载副猪嗜血杆菌PLGA Omp16蛋白微球的制备及其免疫效果的初步研究

为研究载副猪嗜血杆菌(H. parasuis)外膜蛋白Omp16 PLGA微球的生物学特性,本研究以H. parasuis外膜蛋白Omp16为芯材,聚乳酸-羟基乙酸共聚物(PLGA)为壁材,通过复乳溶剂挥发法制备PLGA微球疫苗。通过扫描电镜测定微球的形态、激光粒径仪测定微球的粒径分布。结果显示,PLGA微球呈球性,表面圆整,粒径分布较窄,平均粒径为5.2μm;采用BCA法测定微球的包封率和载药率,结果显示,微球的包封率为70.5%,载药率为5.78%;以透析释药法测定微球的体外释放特性,结果显示,微球体外释放42 d累计释放抗原95.3%。用该微球0.2 mg/次,免疫小鼠二次(间隔14 d)后,采用ELISA法测定小鼠抗H. parasuis IgG水平,结果显示,微球佐剂组小鼠H. parasuis IgG抗体水平显著高于灭活疫苗组(p0.01);腹腔注射H. parasuis LY02株(血清5型)进行攻毒保护试验,结果显示,微球佐剂组小鼠攻毒保护率(81.8%)显著高于灭活疫苗组(63.6%)(p0.05)。以上试验结果表明,制备的PLGA微球具有良好的缓释性能,能增强小鼠体液免疫应答,提高H. parasuis攻毒保护率。本研究为H. parasuis亚单位微球疫苗的制备奠定基础。     

阿维菌素缓释明胶微囊制备工艺及其体外释药特性

以生物可降解材料明胶为囊材,采用单凝聚法制备了阿维菌素明胶微囊,通过L9(34)正交试验设计,对微囊制备工艺进行了优选,所得微囊粒径在2～70μm,其中20～50μm的占78%.药物包封率为(87.61±1.41)%,载药量为(15.77±0.23)%.体外释药试验,微囊释药符合一级动力学特征,t1/2=9.2d,比原药提高5.4倍,表明所制备的明胶微囊具有一定的缓释药物效应.     

用丝素蛋白作壁材制备丝素蛋白-维生素E微胶囊的试验

以具有良好乳化性、稳定性及胶体特性的丝素蛋白溶液作为壁材,与维生素E共混后进行高温喷雾干燥,制备丝素蛋白-维生素E微胶囊。通过优化维生素E与丝素蛋白溶液的配比,提高微胶囊的成囊性能。当维生素E与1%丝素蛋白溶液的质量比为0.5∶1时,制备的微胶囊成囊性能较好,包埋率在90%以上,胶囊颗粒间大小相差不大,囊径在3～5μm之间,囊壁厚度在500 nm～1μm之间。推测丝素蛋白囊壁在高温喷雾干燥过程中其蛋白质结晶区结构发生变化,从而有利于提高对药物的缓释性能。     

沙拉沙星环糊精包合物的制备与体外释放度研究

为了制备沙拉沙星的新剂型,评价其体外释放度,采用响应面法优化沙拉沙星/β-环糊精包合物微囊的制备条件,用扫描电子显微镜(SEC)进行表征试验,对环糊精包合物微囊的粒径和释放度进行评价。响应面法优化后的参数为沙拉沙星和β-环糊精混合液以300 r/min转速在50℃下搅拌4 h,粒径试验表明包合物粒径平均值为1.0μm。体外释放度试验表明,SAR/β-CD包合物在60 min后累积溶出度达到97%左右并保持稳定,物理混合物60 min后累积溶出度仅63%左右,SAR粉剂在60 min后累积溶出率仅74.4%左右。将沙拉沙星成功制备成一种新型包合物制剂,提高了药物的释放性质,对沙拉沙星的推广具有积极意义。     

Fowl cholera: influence of Bordetella avium on vaccinal immunity of turkeys to Pasteurella multocida

Turkeys exposed to Bordetella avium were vaccinated against fowl cholera with live Pasteurella multocida vaccine. Previous exposure to B. avium resulted in impairment of systemic immunity conferred by the vaccine: 86% of the vaccinated turkeys exposed to B. avium at 1 day old developed lesions or died of fowl cholera after challenge at 15 weeks old with virulent P. multocida. Of vaccinated turkeys not previously exposed to B. avium, only 26% had lesions or died of fowl cholera.     

喷雾-复凝聚法制备小反刍兽疫缓释微囊疫苗的研究

建立了喷雾-复凝聚法制备灭活PPR微囊疫苗的工艺方法,并对制备的疫苗进行了主要性能指标测定和动物试验。结果显示：三批微囊形态均呈不规则长囊状,平均包埋率为42%,包埋前后灭活PPRV抗原活性得到较好保持。制备的灭活PPR微囊疫苗在免疫绵羊后1个月,中和抗体滴度均能达到1∶20以上,均高于小反刍兽疫弱毒疫苗1∶10的质量标准,最高可达到1∶160;且中和抗体滴度至少能持续7个月,呈现出良好的缓释效果,是一种具有广阔应用前景的新型疫苗。     

白灵菇乳饮料生产关键工艺及其稳定性

将鲜品白灵菇均质处理,用于白灵菇乳饮料的生产。用激光粒度仪分析不同均质时间对白灵菇浆料粒径分布的影响;以乳饮料稳定性为响应值,选取白灵菇浆料添加量、白灵菇浆料添加粒度、复配稳定剂添加量、脱脂乳粉添加量为考察因素,采用响应面法优化白灵菇乳饮料的配方。结果表明：由单因素试验确定复配稳定剂中果胶、羧甲基纤维素和单甘酯的复配比例为1.0∶1.3∶1.7（m/m）;白灵菇浆料添加量8%、白灵菇浆料粒度100 目、复配稳定剂添加量0.3%、脱脂乳粉添加量9%条件下生产的白灵菇乳饮料质地均匀、酸甜适中,稳定性最高,为（     

DNA fingerprinting of plasmid-containing serotype A: 3,4 Pasteurella multocida isolated from cases of fowl cholera in chickens and turkeys

The live, attenuated vaccine strains of Pasteurella multocida have been hypothesized to be responsible for homologous serotype outbreaks of fowl cholera on farms that use the commercial vaccines. We have further hypothesized that the naturally occurring Clemson University (CU) vaccine strain may be transformed to virulence by the acquisition of plasmid DNA. To test this hypothesis, we obtained seven homologous serotype (A:3,4) P. multocida isolates, all plasmid bearing, that were cultured from fowl cholera cases in vaccinated flocks and compared the isolates with the CU reference vaccine by molecular methods. Restriction fragment length polymorphisms (RFLPs) were detected by DNA/DNA hybridization with labeled probes specific for the cya, aroA, and rrn genes of P. multocida. The RFLPs obtained from BglII-digested genomic DNA probed with cya demonstrated no differences among the isolates. Although three isolates probed with aroA showed a RFLP identical to the vaccine strain, five isolates were distinctly different. Isolates probed with rrn grouped into three different restriction patterns that were dissimilar from that of the vaccine strain. Therefore, we have shown that these fowl cholera isolates are different from the CU vaccine strain and that these outbreaks were not vaccine related.     

Differentiation of field isolates of Pasteurella multocida serotype 3,4 from live vaccine strain by genotypic characterization

Fifty-five serotype 3,4 isolates of Pasteurella multocida, isolated from turkeys dead from fowl cholera, were characterized (fingerprinted) genotypically for comparison with the serotype 3,4 live fowl cholera vaccine principally used in turkeys in California. Twenty-three isolates were obtained from turkeys vaccinated with the M9 live vaccine, and 32 additional isolates were from turkeys not vaccinated for fowl cholera. Methods of characterization included restriction endonuclease analysis of chromosomal DNA and ribotyping, a technique for highlighting restriction site heterogeneity of highly conserved ribosomal RNA genes and associated sequences using a radiolabeled rRNA probe. Eight different genotypes or ribotypes were detected in these isolates by the above methods. Of 23 isolates from M9-vaccinated turkeys flocks, 19 were the same ribotype as M9. Thirty of 32 isolates recovered from unvaccinated turkeys were different ribotypes from M9. The remaining two isolates resembled M9 and were recovered from two different flocks placed in succession on a turkey farm where a flock placed previously had been vaccinated with M9, suggesting interflock transmission. Ribotyping and restriction endonuclease analysis appear to be useful tools to aid in the determination of the role that the live vaccine plays in fowl cholera epidemiology.     

禽霍乱蜂胶灭活疫苗对鸡鸭鹅的现场免疫应用效果

对鸡、鸭、鹅健康群和禽霍乱发病群现场应用禽霍乱蜂胶灭活疫苗，结果表明，该疫苗安全可靠，不影响开产日龄和产蛋；保护率高，４个月内保护率为９８．７％～１００％，６个月内保护率为８５％～９５％，６个月以上保护率为６０％～８０％；对禽霍乱暴发群配合内服药物，可于５～７ｄ内迅速控制和扑灭疫情，且不复发     

Fowl cholera immunity induced by various vaccines in broiler minibreeder chickens determined by enzyme-linked immunosorbent assay

Broiler minibreeder hens were vaccinated for protection against fowl cholera at 12 and 21 weeks of age using several vaccination schemes, which included a live Pasteurella multocida (CU strain) vaccine, two commercial polyvalent fowl cholera oil-based bacterins, and two experimentally prepared polyvalent oil-based bacterins. Some treatment groups received only live or killed vaccines, whereas others received a live vaccine at 12 weeks followed by a killed product at 21 weeks. At 42 weeks of age, all birds that received the live CU vaccine twice or once followed by a bacterin survived challenge. Birds that received killed vaccines only were significantly less protected but still showed a respectable survival rate of 86%. All unvaccinated controls died within 72 hr after challenge. At 72 weeks of age, overall protection was lower than that at 42 weeks, regardless of vaccination treatment. Antibody titers were usually higher in birds that received bacterins than in those receiving live vaccines, yet overall protection was still greater in those birds that received the live cholera vaccine twice.