Preparation and Evaluation Of Drug-Containing Chitosan Beads

Sulfadiazine beads were prepared by dropping drug-containing solutions of the positively charged polysaccharide, chitosan, into tripolyphosphate (TPP) solutions. The droplets instantaneously formed gelled spheres by ionotropic gelation, entrapping the drug within a three-dimensional network of the ionically linked polymer. To achieve maximum drug content, high payloads, short gelation times, low TPP concentrations, and a low internal to external phase ratio were required. The chitosan beads showed pH-dependent swelling and dissolution behavior. The beads swelled and dissolved in 0.1N HCl, while they stayed intact in simulated intestinal fluid. The release of sulfadiazine in 0.1N HCl decreased with increasing concentration of TPP, but was independent of the TPP concentration in intestinal fluids. The morphology of the beads was investigated by scanning electron microscopy. The porosity of the beads depended on the method of drying.     

Preparation and Evaluation of Sustained Release Ibuprofen Beads

Sustained release beads of ibuprofen were prepared by a capillary method using cellulose acetate phthalate, surfactants (Tween 80 and Span 80), and polymers (K 100 M Methocel and K 100 LV Methocel). These beads were formulated into capsule and tablet dosage forms. The beads did not disintegrate in simulated gastric fluid; however, they disintegrated in simulated intestinal fluid. The dissolution profiles of ibuprofen beads and dosage forms of beads (tablets and capsules) were conducted in phosphate buffer (pH 7.2) at 37°C. The beads containing Span 80 and K 100 M Methocel resulted in prolonged drug release. The preparation containing Span 80 and equal quantities of both the polymers (K 100 M Methocel and K 100 LV Methocel), also showed good sustained release properties. The formulations prepared with Tween 80 and K 100 LV Methocel released over 90% of the drug in 2 hours indicating no sustained release properties. The beads in tablet dosage form yielded slower dissolution profiles compared to the beads in capsule form which, in turn, had slower release profiles compared to the beads alone. Release of ibuprofen was much slower from tablets after one year of storage compared to tablets immediately after their manufacture.     

Preparation and Evaluation of Sustained Release Ibuprofen Beads

Sustained release beads of ibuprofen were prepared by a capillary method using cellulose acetate phthalate, surfactants (Tween 80 and Span 80), and polymers (K 100 M Methocel and K 100 LV Methocel). These beads were formulated into capsule and tablet dosage forms. The beads did not disintegrate in simulated gastric fluid; however, they disintegrated in simulated intestinal fluid. The dissolution profiles of ibuprofen beads and dosage forms of beads (tablets and capsules) were conducted in phosphate buffer (pH 7.2) at 37°C. The beads containing Span 80 and K 100 M Methocel resulted in prolonged drug release. The preparation containing Span 80 and equal quantities of both the polymers (K 100 M Methocel and K 100 LV Methocel), also showed good sustained release properties. The formulations prepared with Tween 80 and K 100 LV Methocel released over 90% of the drug in 2 hours indicating no sustained release properties. The beads in tablet dosage form yielded slower dissolution profiles compared to the beads in capsule form which, in turn, had slower release profiles compared to the beads alone. Release of ibuprofen was much slower from tablets after one year of storage compared to tablets immediately after their manufacture.     

用于吸附氟离子的EGDE交联载镧壳聚糖的制备与表征

利用戊二醛(GLA)交联并负载La3+的壳聚糖吸附净化高氟地下水时,反应不完全的戊二醛可能会溶出而产生较大的生物毒性。选用低毒的乙二醇二缩水甘油醚(EGDE)替代GLA,对壳聚糖实施交联改性,生成交联壳聚糖微球(CEB),然后在CEB表面螯合La3+,制备新型除氟剂(CEB-La)。结果表明,交联温度是影响CEB-La吸附性能的最主要因素,交联的适宜条件为EGDE与CS的-NH2物质的量比为1∶2,20℃反应4h;螯合的适宜条件为将CEB按投加量2g/L加到0.020mol/L的La3+溶液中,40℃反应3h。所得到的吸附剂具有良好的稳定性,对质量浓度20mg/L含氟水的F-去除率达96%。红外光谱分析表明,EGDE与壳聚糖的-NH2、C6-OH发生交联反应,形成的交联产物CEB中,仲羟基与La3+配位。X射线衍射分析表明,壳聚糖微球在制备过程中结晶能力下降,有利于La3+的负载和F-的吸附,除氟剂中的镧主要以La-O化物的形式存在。     

Preparation and Evaluation of Controlled Release Propranolol Hydrochloride Beads

Abstract

Conventional pan coating method was utilized to prepare propranolol-HCl sustained release coated beads. Eudragit RS 100 was used as release controlling materials. Overcoating of the beads with beeswax was also investigated. The beads were characterized for their particle size distribution, drug loading efficiency and their dissolution behaviour in 0.1N HCl, Most of the finished beads (72.4%) fall in the particle size range 800–1700 um. The actual drug content, calcu-lated as opposed to the theoretical drug content were 77.6% and 74.2% of the drug for the beads having particle size range 1700–1250 um and 1250–800 um respectively, The coating level of the polymer, the particle size of the beads and overcoating with beeswax play a major role in determining the release rate of the drug from the coated beads.     

Preparation and Evaluation of Controlled Release Propranolol Hydrochloride Beads

Conventional pan coating method was utilized to prepare propranolol-HCl sustained release coated beads. Eudragit RS 100 was used as release controlling materials. Overcoating of the beads with beeswax was also investigated. The beads were characterized for their particle size distribution, drug loading efficiency and their dissolution behaviour in 0.1N HCl, Most of the finished beads (72.4%) fall in the particle size range 800-1700 um. The actual drug content, calcu-lated as opposed to the theoretical drug content were 77.6% and 74.2% of the drug for the beads having particle size range 1700-1250 um and 1250-800 um respectively, The coating level of the polymer, the particle size of the beads and overcoating with beeswax play a major role in determining the release rate of the drug from the coated beads.     

Drug Release from Spray Layered and Coated Drug-Containing Beads: Effects of pH and Comparison of Different Dissolution Methods

Based on dissolution profiles of three model drugs on spray layered beads with the same percentage of Aquacoat® coating, it was concluded that in vitro dissolution of oral controlled–release formulations should be performed in both gastric and intestinal media for ionizable drugs. Ketoprofen (weak acid, pK_a 4.8), nicardipine HCl (salt of weak organic base, pK_a8.6), and acetaminophen (very weak organic acid, pK_a9.7, not ionized at physiologic pH) provided different dissolution characteristics in enzyme–free simulated gastric fluid (pH 1.4) and enzyme–free simulated intestinal fluid (pH 7.4), indicating that the rate of drug release was pH dependent and related to drug ionization even though the solubility of the coating (ethylcellulose) is pH independent. In acidic media, ketoprofen release from the beads containing low–level coating (3%) was slower than that of nicardipine HCl, with the opposite holding true in basic media. Acetaminophen was released at approximately the same rate in both acidic and basic media. A comparison of drug release profiles for nicardipine HCl nude beads was also investigated among three different dissolution methods: USP dissolution apparatus I (basket method, 50 rpm), USP dissolution apparatus II (paddle method, 50 rpm), and USP dissolution apparatus III (Bio–Dis®, Van–Kel Industries, 5 and 10 dpm). Release profiles obtained from all methods were similar, indicating that the three dissolution methods were comparable.     

载银壳聚糖微球的制备及其抗菌性研究

采用乳化交联法制备出载银壳聚糖微球,考察了壳聚糖相对分子质量、乳化剂用量、油水比和硝酸银浓度对微球形貌和载银量、包封率的影响,并通过抑菌圈实验对其抗菌性能进行了评价。结果表明:较低相对分子质量的壳聚糖有利于微球制备,而且所得的粒径较小,其粒径介于1～3μm,载银量可高至256 mg/g,银的包封率可达66.8%。抗菌试验结果表明,无银壳聚糖微球对大肠杆菌和金黄色葡萄球菌有一定的抑菌性,加载银后的微球则具有极为显著的抗菌效果。     

Avicel RC-591/Chitosan Beads by Extrusion-Spheronization Technology

Beads were successfully prepared using the combination of Avicel RC-591 and chitosan using extrusion and spheronization technology. The effects of different viscosity grades of chitosan (SEACURE 142, 242, 342 and 442) on bead formation and on release profiles were examined using acetaminophen as a model drug. Incorporation of higher viscosity grades of chitosan yielded beads with rough surfaces and slower release characteristics. Seacure 342 was chosen for further studies using acetaminophen and theophylline as model drugs of different solubilities. Beads were prepared with varying proportions of Seacure 342 and Avicel RC-591 (20% drug loading). Drug release from the beads varied with the dissolution method used. Beads were swollen in 0.1 N HC1 while the bead structure remained intact. In water, the beads exhibited gel-like structures.     

Avicel RC-591/Chitosan Beads by Extrusion-Spheronization Technology

Abstract

Beads were successfully prepared using the combination of Avicel RC-591 and chitosan using extrusion and spheronization technology. The effects of different viscosity grades of chitosan (SEACURE 142, 242, 342 and 442) on bead formation and on release profiles were examined using acetaminophen as a model drug. Incorporation of higher viscosity grades of chitosan yielded beads with rough surfaces and slower release characteristics. Seacure 342 was chosen for further studies using acetaminophen and theophylline as model drugs of different solubilities. Beads were prepared with varying proportions of Seacure 342 and Avicel RC-591 (20% drug loading). Drug release from the beads varied with the dissolution method used. Beads were swollen in 0.1 N HC1 while the bead structure remained intact. In water, the beads exhibited gel-like structures.     

纳米磁性壳聚糖载药体的制备与体外释药评价

以自制Fe3O4磁性纳米为磁性靶向核,在乳液体系中制备壳聚糖／三聚磷酸钠／5-Fu磁性壳聚糖纳米载药体（TCF）,经一定比例的PHB和PEG混合外包覆,得到载药率为16．56％的磁性纳米微囊（PTCF）,通过红外光谱、x-射线粉末衍射、透射电镜和振动磁强计表征,结果显示,TCF、PTCF分别为粒径15nm和20nm均匀颗粒,25℃时的矫顽力和剩磁均趋于零,表现出超顺磁性;体外释药行为显示,PTCF无突释现象,释药速率随PHB和PEG用量可控,具备磁靶向控释药物的潜在性质。     

基于壳聚糖的防污涂膜制备及性能评估

在最佳成膜条件下,用流延法制备6种壳聚糖膜。比较了6种膜的物理特性、抑菌效果及对低浓度铜离子的吸附性能。结果表明,6种膜均具有良好的吸水性和透气性,加入交联剂戊二醛会改变膜的柔韧性,加入纳米TiO2的膜透光率降低。6种膜都具有一定的抑菌效果,而且吸附铜离子后抑菌效果有所增强。6种壳聚糖膜对铜离子的吸附具有快速高效的特点,为基于壳聚糖的自抛光、低表面能新型海洋防污损涂膜的研发提供了依据。     

Preparation and In Vitro Evaluation of Chitosan Matrices Cross-Linked by Formaldehyde Vapors

Rifampicin-chitosan matrices were prepared by a chemical cross-linking method to develop a sustained-release form. The effects of cross-linking agent (formaldehyde) on the drug release rate and release kinetics were investigated in this study. Moreover, the kinetics of rifampicin released from chitosan matrices exposed to formaldehyde vapors for predetermined time intervals were analyzed using Ritger and Peppas exponential equation. The in vitro release kinetics exhibited a non-Fickian transport model. Increasing the exposure time to formaldehyde vapors decreased the release rate of rifampicin from chitosan matrices as a result of formation of greater structural strength and tighter texture.     

Preparation and Dissolution Characteristics of Prolonged Release Mebeverine-HCL Beads

Different batches of slow release mebeverine-HCl beads were prepared by pan coating technique using different release retarding polymers viz Eudragit RL₁₀₀, Eudragit RS₁₀₀ and Ethyl cellulose. The thickness of the coats was controlled by changing the amounts of the added polymers. Pre- and overcoating of the beads with bees wax was also carried out. Mixtures of pre-waxed Eudragit RS₁₀₀ coated and uncoated beads in different ratios were prepared to control both drug content and release.

Dissolution profiles of mebeverine HCl from the prepared beads were investigated using USP XX rotating basket method. Prolonged release of mebeverine-HCl was obtained from different batches of the coated beads with the advantage of no initial dumping of the water soluble drug. The release of mebeverine-HCl from the beads coated with acrylic resins and ethyl cellulose as well as waxed acrylic resins coated beads was diffusion controlled according to Higuchi model. Beads coated with ethyl cellulose showed a different release pattern when pre-or overcoated with wax. By altering the ratios of prewaxed Eudragit Rs₁₀₀ coated and uncoated beads in formulated mixtures, it was possible to control both mebeverine-HCl content and release rate.     

Preparation and Dissolution Characteristics of Prolonged Release Mebeverine-HCL Beads

Different batches of slow release mebeverine-HCl beads were prepared by pan coating technique using different release retarding polymers viz Eudragit RL₁₀₀, Eudragit RS₁₀₀ and Ethyl cellulose. The thickness of the coats was controlled by changing the amounts of the added polymers. Pre- and overcoating of the beads with bees wax was also carried out. Mixtures of pre-waxed Eudragit RS₁₀₀ coated and uncoated beads in different ratios were prepared to control both drug content and release.

Dissolution profiles of mebeverine HCl from the prepared beads were investigated using USP XX rotating basket method. Prolonged release of mebeverine-HCl was obtained from different batches of the coated beads with the advantage of no initial dumping of the water soluble drug. The release of mebeverine-HCl from the beads coated with acrylic resins and ethyl cellulose as well as waxed acrylic resins coated beads was diffusion controlled according to Higuchi model. Beads coated with ethyl cellulose showed a different release pattern when pre-or overcoated with wax. By altering the ratios of prewaxed Eudragit Rs₁₀₀ coated and uncoated beads in formulated mixtures, it was possible to control both mebeverine-HCl content and release rate.     

对苯甲酰氨基苯甲酰壳聚糖制备与表征

在乙酸体系中,通过对苯甲酰氨基苯甲酰氯与壳聚糖在超声波振荡下反应制备对苯甲酰氨基苯甲酰壳聚糖。探讨超声波作用下,反应时间、反应温度及反应物投料比对壳聚糖衍生物取代度的影响。采用红外光谱、紫外光谱方法对目标产物进行了结构表征。研究结果表明,产物具有对苯甲酰氨基苯甲酰壳聚糖的结构特征,并具有较好的表面活性、较好的溶解性能和一定的吸收紫外线的能力,有望用于日用化妆品中。     

壳聚糖微球的制备与应用

壳聚糖微球是一种典型的生物医用材料,主要应用于药物、杀菌、基因治疗等领域.目前,壳聚糖微球的常用制备方法有化学交联法、离子交换法、复凝聚法、喷雾干燥法和乳化分散法等.分析了壳聚糖微球的主要制备方法,评述了其在药物负载、伤口杀菌、基因治疗等领域的应用.     

镀银磁性PMMA微球的制备

采用化学镀法制得了表面包覆银层的导电磁性聚甲基丙烯酸甲酯(PMMA)微球。对粗糙度不同的微球进行镀银,研究了银在微球上的沉积机理。表面改性使磁性PMMA微球功能化,具有和银强烈结合的能力,从而得到包覆均匀的导电磁性微球。研究了硝酸银和磁性微球的含量对包覆效果及导电性能的影响,并通过SEM和EDS对镀银磁性微球的表面形貌及组成进行了分析。     

苦参碱/羧甲基壳聚糖/磷酸化壳聚糖纳米粒子的制备及性能表征

为了克服壳聚糖只能溶于酸性水溶液的局限,对壳聚糖进行了化学修饰,通过引入磷酸基官能团,合成了可溶于中性水的磷酸化壳聚糖.以磷酸化壳聚糖和羧甲基壳聚糖为基材,采用聚电解质复合法制备了苦参碱/羧甲基壳聚糖/磷酸化壳聚糖纳米粒子水分散制剂.测试结果表明,纳米粒子的平均粒径为l00～200nm,纳米粒子对苦参碱的负载率最高可达66.2%.     

壳聚糖改性纤维素共混复合物的制备及性能

利于壳聚糖共混改性纤维素,介绍了共混改性复合物的制备方法,并利用红外光谱(FT-IR)、扫描电子显微(SEM)、x射线衍射(XRD)、热失重分析(TGA)、平衡水分含量及力学性能的测试对共混复合物的特征进行研究.结果表明,在共混复合物中纤维素和壳聚糖具有良好的相容性,没有相分离发生;共混壳聚糖后,随着壳聚糖含量的增加,...