Microcapsules formulated in the enteric coating copolymer Eudragit L100 as delivery systems for oral vaccination against infections by gastrointestinal nematode parasites

Microcapsules using the copolymer of methacrylic acid (Eudragit L100) were formulated for oral delivery of vaccines against the enteral/parenteral nematode parasite Trichinella spiralis. Antigenic preparations from first stage larvae (L1) of T. spiralis were microencapsulated in Eudragit L100. The microcapsules prepared by the spray drying method were resistant to acid pH, although the antigen was rapidly released under neutral and basic environmental conditions. The native protein conformation and biological activity was preserved in the microcapsules, as assessed by SDS-PAGE and ELISA. When administered to NIH mice, the antigen loaded microcapsules protected against infection by T. spiralis at both the intestinal and muscular levels, the worm burden diminishing by 45.58 and 53.33%, respectively. Furthermore, following administration of the microparticles an increase of the serum IgG1 response, a marker for the Th2 type response, was evident. These results indicate that microcapsules formulated with anionic biocompatible polymers such as Eudragit may be useful for oral vaccination against nematode infections.     

左旋多巴微囊漂浮片的处方优选

摘 要 目的： 优选左旋多巴微囊漂浮片的处方。方法: 高效液相色谱法测定左旋多巴与苄丝肼的含量,以漂浮片释放度得分为指标,采用正交试验优选左旋多巴微囊漂浮片的处方,并对其体外释药特性进行评价。结果: 建立的测定左旋多巴胃内漂浮片中左旋多巴与苄丝肼含量的高效液相色谱法,符合方法学要求。优化的微囊漂浮片处方组成为硬脂酸：主药：丙烯酸树脂：HPMC=2∶5∶2∶1,平均片重为550 mg。验证试验结果表明该微囊漂浮片具有漂浮、缓释、可分剂量使用等特性。结论: 优选出的复方左旋多巴微囊漂浮片处方合理,生产工艺稳定、可行。     

含ZnS的壳聚糖-阿拉伯胶含药微囊的制备及研究

目的本文以壳聚糖和阿拉伯胶为囊材,利用复凝聚法制备包裹非甾体抗炎药物布洛芬的微囊,引入ZnS纳米,增强其缓控释性能。方法将含乙酸锌的壳聚糖溶液与含Na2S的阿拉伯胶溶液混合,以布洛芬为模型药物,通过复凝聚法制备包裹非甾体抗炎药物布洛芬的复合微囊,以微囊的药物包封率与载药量为制备工艺优化指标,通过L9（34）正交实验得出微囊的最佳制备工艺条件。同时用转篮法在肠液条件下进行体外溶出的测定。结果壳聚糖浓度为0.2%、成囊pH为4.5、成囊温度为45℃、搅拌速度为200 rpm。交联剂戊二醛用量0.6mL,乙酸锌0.05M,硫化钠0.05M为最佳工艺。引入纳米ZnS的微囊比未引入纳米ZnS的微囊及市售的片剂具有更好的缓控释性能。结论引入纳米ZnS离子,并以最佳制备工艺条件制备含药微囊,工艺稳定,具有良好的缓控释作用。     

Enhanced Bioavailability and Dissolution of Atorvastatin Calcium from Floating Microcapsules using Minimum Additives

Atorvastatin calcium, a lipid-lowering drug, is much less bioavailable because of reduced solubility in acidic media. Multiple-unit floating microcapsules of Atorvastatin calcium (ATC) were developed to expand the gastric residence time of the drug, as ATC has maximum rate of absorption in the upper GI tract. Floating microcapsules were prepared by Emulsion-solvent evaporation technique through incorporation of dioctyl sodium sulphosuccinate (DSS) as a dissolution enhancer. The microcapsules were assessed for shape, size, drug entrapment efficiency, stability and in-vitro drug dissolution rate and were subjected to SEM, DSC and PXRD studies. The ATC-loaded floating microcapsules were spherical in shape and had the particle size of about 28.10 μm and drug-loading efficiency of about 96.55 %. The floating microspheres containing DSS had significantly higher drug dissolution rates than those without DSS. The best formulation, AT4, consisting of Ethyl cellulose, DSS and Poly Ox®, had a maximum drug dissolution rate of 97.86 %, as compared to Storvas 80 mg (Ranbaxy Ltd, as a reference) which had a rate of only 54% during a period of 12 h in acidic media. A pharmacokinetic study performed on albino rabbits illustrates that the bioavailability of AT4 floating microcapsules significantly increased to nearly 1.7 times that of Storvas 80 mg. The present study indicates that the use of multi-unit floating microcapsules for delivery of ATC can improve its bioavailability.     

5000/壳聚糖水凝胶微球模板的载肝素层层自组装微胶囊

静电层层自组装是微胶囊载药简单有效的方法。本文采用硫酸钠沉淀的方法制备了具有正电荷的壳聚糖微球模板,通过层层自组装的方法装载抗凝血药物肝素。壳聚糖（CS）作为聚阳离子和肝素作为聚阴离子,在壳聚糖微球的模板上层层自组装形成{CS/Hep}3。{CS/Hep}3包被壳聚糖微球模板的微胶囊通过荧光倒置显微镜、激光共聚焦显微镜和激光粒度分析进行了表征。壳聚糖和肝素的层层自组装过程通过Zeta电位分析进行了监测。结果表明{CS/Hep}3包被壳聚糖微球模板的微胶囊平均直径1μm,包封率和载肝素量分别为83.8%和3.05%。     

尼莫地平肠溶微囊的制备及体外释放度考察

目的：优化尼莫地平肠溶微囊的制备工艺并对其体外释放度进行考察。方法：以纤维醋法酯（CAP）为载体材料,利用单凝聚法,通过正交试验设计,考察囊材与囊芯比、溶解cAP所需磷酸氢二钠pH值及量、span-80量及凝聚剂用量、成囊温度等因素对微囊包封率及载药量的影响,初步筛选出最佳处方工艺条件。此外,还建立了紫外分光光度法测定微囊的栽药量与包封率,考查其体外释放度。结果：所得微囊外观圆整,测得平均包封率为80．4％,平均载药量为41．7％。结论：该制备方法简单易行,所制得的微囊肠溶效果理想。     

肺靶向汉防己甲素缓释微囊的长期毒性研究

目的：为肺靶向汉防己甲素（TET）缓释微囊临床研究提供依据。方法：以正常大鼠组,生理盐水组和该微囊的高,中,低剂量给药组进行试验。将给药后大鼠的体征,血液学生化学指标及病理组织学特征等作为指标,进行肺靶向缓释微囊混悬注射液的长期毒性评价。结果：与正常大鼠组,生理盐水组和TET微囊低剂量组的各项指标表明三者均无明显改变,高剂量组所产生的异常变化经停药后,基本恢复正常,结论：肺靶向汉防己甲素缓释微囊基本安全,可用于临床研究。     

The release of diazepam from poly(hydroxybutyrate-hydroxyvalerate) microspheres

Microspheres based on a poly(hydroxybutyrate-hydroxyvalerate) copolymer (PHBV) (Mw = 630 kD, 21% mol HV) were loaded with diazepam using different emulsion-solvent evaporation processes. Gelatin was used as a strategy to alter the release profile of the incorporated drug. The mean diameter of microspheres was from 30-40 micron. Drug-release from the microspheres over a 30-day period showed a characteristic triphasic release pattern with an initial burst effect, but was linear over the same period and without a burst effect when gelatin was used as a coating agent. Scanning electron microscopy revealed that the microspheres had different structures depending upon their method of preparation.     

Neutron-capture therapy of murine ascites tumor with gadolinium-containing microcapsules

Summary Gadolinium-containing microcapsules were evaluated as an agent for gadolinium neutron-capture therapy. Mice were inoculated intraperitoneally with 10⁷ Ehrlich ascites tumor cells and gadolinium microcapsules and exposed to thermal neutrons for 12 min (approximately 1.86×10¹² neutrons cm^–2). Significantly more mice given gadolinium microcapsules than those given placebo microcapsules or control survived for 60 days and considerably longer (P<0.0001), indicating that gadolinium neutron-capture reactions effectively suppressed the growth of ascites tumor cells in mice. The results suggest that these microcapsules are an effective gadolinium carrier for neutron-capture therapy.Abbreviation MG meglumine gadopentetate     

Polyacrylate resin microcapsules for taste masking of antibiotics

Abstract

Various microencapsulated dosage forms were prepared to limit the release of an antibiotic in solution for up to 3 days and in the oral cavity following per oral administration. An experimental antibiotic, clarithromycin (TE-031), was used in these studies. The drug was first encapsulated in gelatin followed in some cases by crosslinking with glutaraldehyde. The gelatin microcapsules were then coated with acrylic resins (Eudragit®), whose solubility properties vary according to pH. A non-solvent coacervation technique was used to apply the Eudragit resins. It was found that crosslinking the gelatin retarded release of TE-031 somewhat relative to that from uncrosslinked gelatin microcapsules in a 72 h release experiment conducted at room temperature. Coating the gelatin microcapsules with Eudragit resins L100, S100, or E100 slowed the release of TE-031 further still; less TE-031 was released over 72 h from the Eudragit-coated formulations prepared with crosslinked gelatin compared with formulations prepared with uncrosslinked gelatin. The Eudragit ElOO-coated crosslinked gelatin microcapsule formulation was most effective in preventing release of the TE-031 under simulated conditions of storage in an aqueous solution.