盐酸洛美沙星温度敏感眼用凝胶的制备研究

为了制备盐酸洛美沙星温度敏感型眼用原位凝胶,试验采用冷溶法制备盐酸洛美沙星眼用温度敏感原位凝胶,搅拌子法测定胶凝温度,正交设计-极差分析法优化盐酸洛美沙星眼用温度敏感原位凝胶处方,运用无膜溶出法考察盐酸洛美沙星眼用温度敏感原位凝胶的体外释放行为。结果表明:盐酸洛美沙星眼用温度敏感原位凝胶的最佳处方为19%泊洛沙姆407、1.4%泊洛沙姆188、0.1%海藻酸钠,优化处方在泪液稀释前后的胶凝温度分别为25.9℃、35.2℃,p H值为7.16,4 h基本溶蚀释药完全。在模拟泪液中,盐酸洛美沙星温度敏感原位凝胶稀释前后均具有温度敏感特性,凝胶的p H值符合眼内局部用药的生理要求,具有明显的缓慢溶蚀释药的特性。     

原位凝胶基质的应用现状和研究进展

原位凝胶产生胶凝的机制较为复杂,目前作为原位凝胶基质的高聚物种类较多,总体可分为全合成的原位凝胶基质材料与天然及半合成的原位凝胶基质高聚物材料。在两种类型的原位凝胶基质中分别选取了目前主要应用的丙烯酸类原位凝胶基质卡波姆、非离子原位凝胶基质材料泊洛沙姆、纤维素类原位凝胶基质、壳聚糖等,文章对其胶凝机制、应用现状及未来发展趋势等进行了简要介绍。     

盐酸米诺环素络合物温敏凝胶的制备及初步评价

【目的】试验旨在制备一种能在局部递送盐酸米诺环素的络合物温敏凝胶。【方法】将盐酸米诺环素与Ca²⁺形成的络合物装载入泊洛沙姆407（P407）与泊洛沙姆188（P188）制备形成的温敏凝胶中，对其温敏性、表征结构、药物含量、稳定性、体外释放效果及抗菌性能进行研究。【结果】本研究制备的盐酸米诺环素温敏凝胶，在其组方为每50 mL凝胶中含米诺环素0.25 g、P407 8 g、P188 1.5 g、CaCl₂ 0.01 g、乙酸调pH至4.0±0.2、其余量为去离子水时，外观性状显示为淡黄色澄清溶液，透明度均匀，无沉淀及药物析出，温敏性能良好（31℃即可发生胶凝）；扫描电镜下可见该凝胶形成的网格孔洞结构致密且分布均匀；平均粒径为11.5 nm，Zeta电位为－3.8 mA；体外释放药物时间长达48 h，与原料药相比明显延长；在抗菌性能检测中，与原料药相比，同浓度盐酸米诺环素络合物温敏凝胶的抑菌能力没有降低，且体外抑菌时间明显延长，抑菌效果良好。【结论】本研究成功制备了一种盐酸米诺环素络合物温敏凝胶，通过模拟体外释放试验及体外抑菌曲线表明该凝胶能显著延长药物作用时间，提高药物利用率，可为临床使用盐酸米诺环素提供一种新的给药方式。     

采用泊洛沙姆为佐剂的O型口蹄疫多肽疫苗对大鼠脾细胞的增值作用

为研究泊洛沙姆作为佐剂的O型口蹄疫多肽疫苗对小鼠脾淋巴细胞增殖的影响,采用四甲基偶氮唑盐法(MTT)检测不同浓度的泊洛沙姆407、FMDV-O型泊洛沙姆佐剂多肽疫苗(多肽浓度50μg/m L)、FMDV O型多肽抗原液(7.06 mg/m L,用PBS稀释至50μg/m L)及FMDV O型油乳佐剂多肽疫苗(多肽浓度50μg/m L)对伴刀豆球蛋白A(Concanavalin A,Con A)处理淋巴细胞的增殖率。结果表明,与空白对照组相比较,泊洛沙姆各浓度对脾细胞均有增殖作用,多肽疫苗在高浓度的时候对细胞有抑制作用,随着作用浓度的降低,又进而转为细胞增殖作用。     

泊洛沙姆-辛酸法对鸡卵黄脱脂条件的研究

本文就泊洛沙姆浓度、辛酸浓度、泊洛沙姆沉淀法沉淀离心条件对泊洛沙姆-辛酸法对鸡卵黄脱脂的影响进行了探讨。实验结果表明:泊洛沙姆浓度、辛酸浓度分别对卵黄脱脂存在不同程度影响,卵黄稀释液沉淀离心条件对卵黄脱脂影响不大。蛋黄稀释液不经离心直接纱布过滤,辛酸浓度为0.2%,泊洛沙姆浓度分别为0.6%、0.8%、1%、1.2%、1.4%、1.6%、1.8%的7个处理中,以1.2%浓度的提取效果最好;泊洛沙姆浓度为1.2%,辛酸浓度为0.2%,蛋黄稀释液经离心处理和纱布过滤处理对卵黄脱脂影响不大;泊洛沙姆浓度为1.2%,蛋黄稀释液纱布过滤处理,辛酸浓度分别为0、0.1%、0.2%、0.3%、0.4%、0.5%的6个处理中,以0.2%浓度的提取效果最好。     

泊洛沙姆对鸡卵黄脱脂作用的研究

通过对鸡法氏囊高免蛋卵黄进行泊洛沙姆脱脂研究证明:泊洛沙姆对鸡卵黄具有良好的脱脂作用,并且具有脂类自然沉降速度快、对抗体影响小、简化工艺以及本身无毒、无害的特点,适合于卵黄的综合开发利用。     

泊洛沙姆对鸡卵黄脱脂作用的研究

通过对鸡法氏囊高免蛋卵黄进行泊洛沙姆脱脂研究证明：泊洛沙姆对鸡卵黄具有良好的脱脂作用，并且具有脂类自然沉降速度快、对抗体影响小、简化工艺以及本身无毒、无害的特点，适合于卵黄的综合开发利用。     

注射用温敏型原位凝胶研究进展

温敏型原位凝胶因具有良好的流动性、高效的生物利用度、较长的滞留时间以及良好的药物缓释性能等优点成为了新型药物递送系统的主要研究对象,已成为国内外研究新型药物递送系统的一个热点。以近年来国内外注射用温敏型原位凝胶相关文献为基础,对其主要种类、质量控制以及应用的研究进行总结,进而为注射用温敏型原位凝胶的研发提供参考与借鉴。     

蛋白载体温敏凝胶制备及释放度研究

为研究温敏凝胶作为疫苗或多肽蛋白类药物的佐剂或载体的可行性,本研究采用泊洛沙姆为温敏凝胶基质,以牛血清白蛋白为模型蛋白配制了两种不同配比的凝胶,采用试管倒置法,分别测定了添加牛血清白蛋白前后的胶凝温度的变化,采用Bicinchoninicacid蛋白含量测定法测定了以水为介质的BSA释放度,结果显示,添加BSA后胶凝温度和空白凝胶无差异,且两种不同配比的释放行为无显著差异,均为一级释放动力学,且释放机制为Fickian扩散。     

RP-HPLC法测定CPFL原位凝胶中主药的含量

建立乳酸环丙沙星泊洛沙姆原位凝胶中乳酸环丙沙星含量测定的高效液相色谱法。以流动相为参比溶液,在波长200～400 nm段用紫外分光光度计进行光谱扫描以选择乳酸环丙沙星的入射波长;用Extreme C18柱(5μm,25 cm×4.6 mm)为色谱柱,流动相为0.025 mol/L磷酸溶液(三乙胺调节pH至3)-乙腈(87:13),流速为1.0 mL/min,检测波长为λmax=279 nm,进样量为50μL,采用峰面积外标标准曲线法计算含量。结果表明:乳酸环丙沙星的最大吸收波长为279 nm,峰宽较窄;乳酸环丙沙星检测质量浓度线性范围为1.25～40μg/mL(r=1),平均回收率99.50%(相对标准偏差=1.67%,n=9)。本法操作简便,快速,结果准确可靠,重复性较好,可用于测定乳酸环丙沙星原位凝胶中乳酸环丙沙星的含量。     

Pharmacokinetics of moxifloxacin in rabbits after intravenous, subcutaneous and a long-acting poloxamer 407 gel formulation administration

The pharmacokinetics (PK) of moxifloxacin in healthy white New Zealand rabbits was studied following intravenous (IV) and subcutaneous (SC) administration routes as well as a SC long-acting poloxamer 407 gel formulation (SC-P407). Moxifloxacin concentrations were determined by high-performance liquid chromatography assay with fluorescence detection. Mean half-life for IV, SC and SC-P407 routes was 2.15, 5.41 and 11.09 h. Clearance value after IV dosing was 0.78 l/kg/h. After SC administration, the mean absolute bioavailability was 117% and the C(max) was 1.61 +/- 0.49 mg/l. After SC-P407 administration, the bioavailability was 44% and the C(max) 1.83 was +/-0.62 mg/l. No adverse effects were observed in any of the rabbits following IV, SC and SC-P407 administration of moxifloxacin. Minimal inhibitory concentrations of moxifloxacin against different strains of Staphylococcus aureus from different european countries were used to compute the main pharmacodynamic (PD) surrogate markers of efficacy. The high tolerability of this SC-P407 formulation and the favourable PK behaviour such as the long half-life, acceptable bioavailability and excellent PK-PD ratios achieved indicate that it is likely to be effective in rabbits.     

Evaluation of Intracavitary Chemotherapy Delivery for the Treatment of Mammary Carcinoma

Introduction:  The purpose of this study was to evaluate tolerability and efficacy of local (intracavitary) delivery of paclitaxel from a gel polymer (poloxamer 407) following marginal (histologically incomplete) resection of mammary carcinoma in a mouse model
Methods:  In vitro sensitivity to paclitaxel as well as poloxamer‐taxol mixture (polotax) was determined for 4 human breast tumor cell lines using the MTS‐assay (Promega). Nude mice were then injected with MCF‐7/ADR (Adriamycin^R resistant) cells. Tumor growth was monitored by imaging of luciferase activity with a CCD camera (IVIS system, Xenogen). Primary tumors were allowed to grow to 3 different size ranges. At the time of primary tumor resection, animals were randomly assigned to treatment groups comparing intracavitary (in the wound) polotax to intravenous paclitaxel. Mice were imaged weekly to evaluate tumor regrowth and metastasis.
Results:  All cells lines demonstrated sensitivity to paclitaxel and three of the four cell lines demonstrated improved cytotoxicity with polotax compared to drug delivered alone. One of 9 mice treated with polotax had local regrowth (by 60 days) compared to 6 of 9 mice treated with intravenous paclitaxel. One of 9 mice treated with polotax had distant metastasis at 60 days compared to 5 of 8 mice treated with intravenous paclitaxel. These effects were seen with tumors of all sizes.
Discussion/Conclusions:  Poloxamer delivery of paclitaxel appears to result in improved efficacy compared to paclitaxel alone. Improved local and systemic control of mammary carcinoma is seen following intracavitary poloxamer delivery of paclitaxel compared to paclitaxel alone in this mouse model.     

In vitro and in vivo evaluation of an in situ forming gel system for sustained delivery of Florfenicol

The objective of this study was to develop an injectable in situ forming gel system based on Poloxamer for sustained release of Florfenicol (FFC). The formulations were prepared containing certain amounts of Poloxamer 407 (P407) and Poloxamer 188 (P188) alone or with hydroxylpropyl methylcellulose (HPMC), sodium carboxymethyl cellulose (CMC‐Na), or polyvinyl pyrrolidone (PVP) as polymer additives. The optimal formulation was chosen according to in vitro parameters (gelation temperature, gelation time, pH value, viscosity, and in vitro release). Then the FFC in vivo pharmacokinetic character of the optimal formulation was investigated in dogs with a single dose of 50 mg/kg b.w. under s.c. injection. In vitro release studies, all formulations containing polymer additives had prolonged release time and decreased initial burst to some extent. The optimal formulation containing 0.15% HPMC showed a best sustained release profile for about 128 h with the lowest initial burst in vitro (<40% in 24 h). In vivo, the 20% FFC in situ forming gel provided prolonged drug release time within the therapeutic range for about 100 h, with stable plasma levels and elimination half‐life (t_1/2λz) nine times higher than the control formulation. In conclusion, in situ forming gel is an attractive alternative for FFC sustained release system.     

水牛SOX2基因5'调控序列的克隆与功能分析

为探讨水牛SOX2基因的转录调控机制,本试验克隆获得其长2555 bp 的5'调控序列片段,结合生物信息分析设计了-2263、-1816、-1275、-660和-407 bp 5个缺失体,并分别构建其EGFP表达报告载体,通过生产转基因早期胚胎和转染水牛胎儿成纤维细胞分析各缺失体片段的转录活性。结果发现,除-407 bp以外的各缺失体在猪4.5 d早期胚胎细胞中均能成功启动下游EGFP的表达,且随着片段缩短,其转录活性呈极显著递减趋势(P<0.01);而转染水牛成纤维细胞48 h后,除p-407-EGFP以外的各缺失体报告载体转染组均观察到少数细胞发光,转录活性两两之间差异均极显著(P<0.01),转录活性从高到底排布分别为-2263、-660、-1275和-1816 bp。p-407-EGFP载体在胚胎水平和细胞水平均未观察到荧光。以上结果表明,-660~-407 bp是构成水牛SOX2基因表达不可缺失的部分,-2263~-1816 bp中有非多能细胞特异性的增强子元件存在,而-1816~-1275 bp和-1275~-660 bp均含有多能性细胞特异性的增强子元件。     

醋酸甲羟孕酮(MPA)原位凝胶植入剂对鼠抗生育作用的研究

为达到城市宠物药物避孕的效果,开发醋酸甲羟孕酮原位凝胶植入剂（MPA—PLA）。采用MPA—PLA进行动物体内实验,考察MPA—PLA对小鼠避孕时间和繁殖率的影响及其对大鼠血清中雌二醇（E2）和促黄体生成激素（LH）激素浓度水平的影响。结果表明MPA—PLA对大、小鼠具有长效抗生育作用。     

Campylobacter-induced interleukin-8 responses in human intestinal epithelial cells and primary intestinal chick cells

Campylobacter (C.) jejuni and C. coli can cause gastrointestinal disorders in humans characterized by acute inflammation. Inflammatory signals are initiated during interaction between these pathogens and human intestinal cells, but nothing is known about the stimulation of avian intestinal cells by Campylobacter. Interleukin-8 (IL-8) as a proinflammatory chemokine plays an important role in mobilizing cellular defence mechanism. IL-8 mRNA expression in both human intestinal cells (INT 407) and primary intestinal chick cells (PIC) was determined by quantitative real-time RT-PCR. The secretion of IL-8 protein by INT407 was measured using ELISA. Although C. jejuni and C. coli are considered to be harmless commensals in the gut of birds, the avian Campylobacter isolates investigated were able to induce the proinflammatory IL-8 in PIC as well as in INT407. In an in vitro system, C. jejuni as well as C. coli were able to induce IL-8 mRNA in PIC. Relation between the virulence properties like toxin production, the ability to invade and to survive in Caco-2 cells and the level of IL-8 mRNA produced by INT 407 and PIC after infection with Campylobacter strains was also investigated.