黄原胶亲水性骨架片体外释药的影响因素

以茶碱为模型药物,制备了黄原胶亲水性骨架片,研究了体外释药的影响因素．结果表明,茶碱黄原胶亲水性骨架片的释药速率与骨架片中黄原胶的用量和溶出条件（ 转速、介质离子强度、ｐＨ 值） 有关,但与制备工艺条件无关．溶出介质中离子对其释药机制有影响．黄原胶能有效控制骨架片中药物释放,是一种优良的亲水性骨架材料．     

长春西汀海藻酸钠骨架片体外释药影响因素研究

目的以海藻酸钠为骨架材料 ,制备长春西汀控释骨架片 ,对影响其体外释放的多种因素进行了考察。方法以海藻酸钠为亲水骨架材料 ,粉末直接压片制备长春西汀控释片 ,采用《中华人民共和国药典》2 0 0 0年版二部收载的溶出度测定方法Ⅱ法 (桨法 ) ,测定药物在不同条件下的体外释放度 ,考察海藻酸钠用量及黏度 ,枸橼酸用量 ,释放介质离子强度和pH值对药物体外释放行为的影响。结果与结论海藻酸钠用量及黏度 ,枸橼酸用量 ,释放介质离子强度和pH值均对药物体外释放行为有显著影响。值得注意的是 ,通过调节处方中枸橼酸用量可以使释药行为达零级 ,这为制备长春西汀控释片提供指导 ,有进一步开发的价值。     

神衰果素亲水凝胶缓释骨架片的制备及释药机理的研究

目的制备神衰果素亲水凝胶缓释骨架片.方法以羟丙基甲基纤维素(HPMC)作为缓释材料,采用粉末直接压片工艺制备神衰果素亲水凝胶缓释骨架片,考察HPMC的用量、规格、不同的释药条件对释药速率的影响,并对释药机制作了初探.结果神衰果素亲水凝胶缓释骨架片的体外释药为非Fick扩散,HPMC的用量对药物的释放有较大影响,而HPMC的规格,释放介质的pH值对药物释放影响不大.结论以HPMC作为缓释材料,采用粉末直接压片法制备神衰果素亲水凝胶缓释骨架片,工艺简单,体外缓释效果好.     

双氯芬酸钠甲基纤维素骨架片体外释药的影响因素研究

目的探讨影响甲基纤维素(MC)亲水凝胶骨架片体外释药的因素。方法以双氯芬酸钠(DS)为模型药物,选取MC为骨架材料,观察MC用量、黏合剂选择、压片压力大小对MC亲水凝胶骨架片体外释药的影响。结果 MC用量、压片压力对骨架片的体外释药有较大影响,而黏合剂性质对骨架片的体外释药影响不显著。结论 MC可作为DS骨架片的骨架材料;MC用量、压片压力均影响骨架片的体外释放。     

石杉碱甲凝胶骨架缓释片药物释放因素的研究

目的考察影响石杉碱甲(hupcrzine—A，Hup—A)亲水凝胶骨架片体外释药的各种因素。方法以羟丙基甲基纤维素(HPMC)和乙基纤维素(EC)为骨架材料，湿法制粒压片制备缓释骨架片，并考察HPMC和EC的用量、粘度、HPMC粒度、压片压力及其他辅料对石杉碱甲亲水凝胶骨架片体外释药的影响。结果石杉碱甲亲水凝胶骨架片体外释药符合Higuchi方程。HPMC粒度、粘度、压片压力及辅料种类对石杉碱甲的释放速率没有显性影响。HPMC用量及EC的粘度、用量对石杉碱甲的释放速率有显性影响。结论HPMC及EC用量、EC粘度为影响石杉碱甲亲水凝胶骨架片释放速率的主要因素。     

奥沙西罗亲水凝胶骨架片制备及体外释药特性研究

目的制备奥沙西罗亲水凝胶骨架缓释片,考察处方、工艺以及释放条件对体外释药行为的影响,解析其机理。方法以羟丙甲纤维素(HPMC)为骨架材料,乙基纤维素(EC)为阻滞剂,采用湿颗粒压片法制备奥沙西罗亲水凝胶骨架片,考察HPMC用量、HPMC黏度、EC用量、制备方法、压片压力、释放介质及转速对奥沙西罗骨架片体外释药的影响。结果奥沙西罗骨架片体外释药符合Higuchi方程,药物释放机制是骨架溶蚀和药物扩散的综合效应;HPMC用量与黏度、阻滞剂用量、制备方法、压片压力对释放速率均有显著性影响;释放介质的pH值及转速对释放速率无显著性影响。结论调整处方HPMC用量可制得12 h给药1次的骨架缓释片。     

茶碱缓释片的制备及其初步稳定性考察

目的：考察茶碱羟丙基甲基纤维素（HPMC）骨架片的制备方法及其初步稳定性。方法：以HPMC为骨架材料,采用湿颗粒法制备茶碱缓释片,考察了HPMC用量、HPMC黏度及释放介质pH值对药物体外释放行为的影响,以及光照、高温及高湿度对茶碱缓释片稳定性的影响。结果：HPMC用量和黏度显著影响茶碱释药速率,释放介质pH值对茶碱释药速率影响较小。光照、高温及高湿度不影响茶碱缓释片的含量及释放度。结论：通过使用合适黏度的HPMC及调节HPMC用量可获得具有理想释药行为的茶碱缓释片,且其稳定性良好。     

影响魔芋胶骨架片释药体外释放因素的研究

目的 以魔芋胶为骨架材料,考察药物从魔芋胶骨架片中释放的体外释放因素.方法 以氨茶碱为模型药物,采取湿法制粒压片法制备了氨茶碱魔芋胶骨架片,通过对释放度实验研究了释放介质的离子强度,搅拌转速,不同测定方法,释放介质pH值对骨架片释药的影响.结果 桨法测得的平均释放时间(MDT值)和篮法无明显差别;在不同pH值释放介质中,药物的释放以在pH6.8 PBS中最快,蒸馏水中次之,0.1mol/L盐酸液中最慢;药物释放随释放介质离子强度增加而减慢;药物释放随搅拌转速增加而加快,药物释放机制为扩散和溶蚀机制协同作用.结论 魔芋胶能有效的控制骨架片中药物释放,是一种优良的亲水骨架材料.     

聚氧乙烯骨架缓释片的处方及体外释药机制研究

目的 以聚氧乙烯(PEO)为亲水凝胶骨架制备缓释片剂,并考察其体外释药机制。方法 基于两种规格PEO的用量比与释药速率之间的关系,优化缓释片处方。通过考察片剂的体外释放度和溶蚀比探讨其释药机制,并对不同溶解度药物的体外释放行为进行比较。结果 缓释片体外释药速率与PEO用量比呈线性关系,所得优化处方在12 h内以接近恒速释药,其体外释药与溶蚀过程基本同步,且在所考察用量范围内不同溶解度药物的体外释放度相近。结论 PEO制成的亲水凝胶骨架片缓释性能良好,其体外释药是药物扩散和骨架溶蚀协同作用的结果。     

聚氧乙烯骨架缓释片的处方及体外释药机制研究

目的以聚氧乙烯（PEO）为亲水凝胶骨架制备缓释片剂,并考察其体外释药机制。方法基于两种规格PEO的用量比与释药速率之间的关系,优化缓释片处方。通过考察片剂的体外释放度和溶蚀比探讨其释药机制,并对不同溶解度药物的体外释放行为进行比较。结果缓释片体外释药速率与PEO用量比呈线性关系,所得优化处方在12h内以接近恒速释药,其体外释药与溶蚀过程基本同步,且在所考察用量范围内不同溶解度药物的体外释放度相近。结论PEO制成的亲水凝胶骨架片缓释性能良好,其体外释药是药物扩散和骨架溶蚀协同作用的结果。     

Evaluation of sodium alginate as drug release modifier in matrix tablets

Alginates are useful natural polymers suitable for use in the design of pharmaceutical dosage forms. However, the effects of particle size, viscosity and chemical composition of alginates on drug release from alginate matrix tablets are not clearly understood. Hence, 17 grades of sodium alginate with different particle size distributions, viscosities and chemical compositions were used to prepare matrix tablets at various concentrations to screen the factors influencing drug release from such matrices. Particle size was found to have an influence on drug release from these matrices. Sodium alginate was subsequently classified into several size fractions and also cryogenically milled to produce smaller particle size samples. Cryogenic milling could be successfully applied to pulverize coarse alginate particles without changing the quality through degradation or segregation. This study showed the significance of each alginate property in modulating drug release: particle size is important in initial alginic acid gel barrier formation as it affected the extent of burst release; higher alginate viscosity slowed down drug release rate in the buffer phase but enhanced release rate in the acid phase; high M-alginate might be more advantageous than high-G-alginate in sustaining drug release; and, the effect of increasing alginate concentration was greater with larger alginate particles. This can serve as a framework for formulators working with alginates. Furthermore, the results showed that sodium alginate matrices can sustain drug release for at least 8 h, even for a highly water-soluble drug in the presence of a water-soluble excipient.     

黄连总生物碱胃内漂浮缓释片处方组成的研究

目的：研究黄连总生物碱胃内漂浮缓释片的处方组成及影响因素。方法：以体外释放度为指标,筛选黄连总生物碱胃内漂浮缓释片的处方组成,采用单因素试验法,考察处方中HPMC、海藻酸钠、碳酸氢钠三个因素对其体外释放度的影响。结果：黄连总生物碱胃内漂浮缓释片较优的处方组成为HPMC13.4%,海藻酸钠26.6%,硬脂酸镁5.4%,硬脂酸42%,碳酸氢钠10.6%,HPMC与碳酸氢钠的用量显著影响黄连总生物碱胃内漂浮缓释片的体外释放度。结论：HPMC与海藻酸钠以1：2配伍使用作为片剂亲水凝胶骨架时,其体外释放度良好,且两者具有交互作用。     

Synthesis and Characterization of Sodium Alginate Conjugate and Study of Effect of Conjugation on Drug Release from Matrix Tablet

The aim of the present research work to study the effect of conjugation of the polymer on drug release from the matrix tablets. Sodium alginate L-cysteine conjugate was achieved by covalent attachment of thiol group of L-cysteine with the primary amino group of sodium alginate through the amide bonds formed by primary amino groups of the sodium alginate and the carboxylic acid group of L-cysteine. The synthesised sodium alginate L-cysteine conjugate was characterised by determining of charring point, Fourier transmission-infrared and differential scanning calorimetric analysis. To study the effect of conjugation on drug release pattern, the matrix tablets were prepared using various proportions of sodium alginate and sodium alginate L-cysteine conjugate along with atorvastatin calcium as model drug. The wet granulation technique was adopted and prepared matrix tablets were evaluated for various physical parameters. The in vitro drug release study results suggested that tablet formulated in combination of sodium alginate and sodium alginate L-cysteine conjugate S4 showed 100% after 8 h drug release whereas formulated with only sodium alginate S0 released 40% in 8 h.     

Formulation and evaluation of floating drug delivery system of famotidine

A multiple unit oral floating drug delivery system of famotidine was developed to prolong gastric residence time, target stomach mucosa and increase drug bioavailability. Drug and polymer compatibility was studied by subjecting physical mixtures of drug and polymers to differential scanning calorimetry. Cod liver oil entrapped calcium alginate beads containing famotidine, capable of floating in the gastric condition were formulated and evaluated. The gel beads were prepared by emulsion gelation method by employing sodium alginate alone and mixture of sodium alginate and hydrophilic copolymers such as carbopol 934P and hydroxypropylmethylcellulose K15M grade in three different ratios. The effect of selected factors, such as percentage of oil and amount of copolymers on floating properties was investigated. The beads were evaluated for percent drug loading, drug entrapment efficiency, buoyancy and in vitro drug release. The in vitro drug release study of the beads was carried out in simulated gastric media employing a modified Rosette-Rice test apparatus. Wherein, the apparatus was further modified by incorporating a water jacket to the apparatus to circulate hot water to maintain 37±2° for throughout the release study. All the oil entrapped calcium alginate beads floated if a sufficient amount of oil was used. Beads formulated employing sodium alginate alone could not sustain the drug release up to 8 h, whereas beads formulated with mixture of sodium alginate and copolymers demonstrated sustained release of famotidine up to 8 h. The results suggested that cod liver oil entrapped calcium alginate beads were promising as a carrier for intragastric floating drug delivery of famotidine.     

Evaluation of alginate based mesalazine tablets for intestinal drug delivery.

The aim of this study was to develop the alginate based mesalazine tablets for intestinal delivery. Sodium alginate is a biocompatible, natural polymer with pH-sensitive gel-forming ability. Matrix tablets were prepared with two types of sodium alginate of different amounts. The in vitro release characteristics of mesalazine from alginate tablets were compared with those of the commercial product (Salofalk). X-ray imaging was used to monitor the tablets throughout the gastrointestinal system. Although alginate tablets gave a faster release in an acidic medium compared with the commercial product (Salofalk), the cumulative amount of released drug of the optimum formulation was found to be almost the same as that of the commercial product at the end of 4 h. The alginate type and amount in the matrices played an important role in basic media. The release of the optimum formulation containing low viscosity alginate was found to be almost identical to that of the commercial product in acidic and basic media. Tablets were visualized to determine whether they were located in the terminal ileum or cecum for 3-6 h. Mesalazine-alginate matrix tablet formulations can deliver the drug to the small and large intestine. Thus, the alginate matrix system may be a promising system for the treatment of Crohn's disease involving both the ileum and large intestine.     

Effect of water-soluble carriers on morphine sulfate release from a silicone polymer.

The influence of gelatin, sodium lauryl sulfate, lactose, and sodium alginate on morphine sulfate diffusion from cylindrical silicone polymer pellets was examined in isotonic pH 7.4 phosphate buffer. These water-soluble carriers caused the pellets to swell in aqueous media. Sodium alginate exerted the greatest influence on drug release. The morphine sulfate diffusion rate from the cylindrical pellets increased as the matrix alginate content increased up to 20%. Water-soluble carrier incorporation into silicone polymeric matrixes permits controlled release of water-soluble drugs that otherwise would be released extremely slowly from the polymer. Drug diffusion from the silicone matrix containing sodium alginate followed second-order kinetics. The release mechanism probably involves the creation of pores or pathways through the matrix secondary to the swelling.     

Preparation and release characteristics of polymer-reinforced and coated alginate beads

Polymeric reinforcement and coatings of alginate beads were carried out to control the release rate of drug from alginate beads. A poorly water-soluble ibuprofen (IPF) was selected as a model drug. A commercially available Eudragit^® RS100 was also used as a polymer. Effects of polymeric contents, the presence of plasticizers and amount of drug loading on the release rate of drug were investigated. The release rate of drug from alginate beads in the simulated gastric fluid did not occur within 2 h but released immediately when dissolution media were switched to the simulated intestinal fluid. No significant difference of release rate from polymer-reinforced alginate bead without plasticizers was observed when compared to plain (simple) beads. However, the release rate of drug from polymer-reinforced alginate beads was further sustained and retarded when aluminium tristearate (AT) as a plasticizer was added to polymer. However, polyethylene glycol 400 (PEG400) did not change the release rate of drug from alginate beads although PEG400 was used to improve dispersion of polymer and sodium alginate, and plasticize Eudragit^® RS100 polymer. The presence of plasticizer was crucial to reinforce alginate gel matrices using a polymer. As the amount of drug loading increased, the release rate of drug increased as a result of decreasing effects of polymer contents in matrices. The significantly sustained release of drug from polymer-coated alginate beads occurred as the amount of polymer increased because the thickness of coated membrane increased so that cracks and pores of the outer surface of alginate beads could be reduced. The sustained and retarded action of polymer-reinforced and coated beads may result from the disturbance of swelling and erosion (disintegration) of alginate beads. From these findings, polymeric-rein-forcement and coatings of alginate gel beads can provide an advanced delivery system by retarding the release rate of various drugs.     

Preparation and release characteristics of polymer-coated and blended alginate microspheres

To prevent a rapid drug release from alginate microspheres in simulated intestinal media, alginate microspheres were coated or blended with polymers. Three polymers were selected and evaluated such as HPMC, Eudragit RS 30D and chitosan, as both coating materials and additive polymers for controlling the drug release. This study focused on the release characteristics of polymer-coated and blended alginate microspheres, varying the type of polymer and its concentration. The alginate microspheres were prepared by dropping the mixture of drug and sodium alginate into CaCl(2) solution using a spray-gun. Polymer-coated microspheres were prepared by adding alginate microspheres into polymer solution with mild stirring. Polymer-blended microspheres were prepared by dropping the mixture of drug, sodium alginate and additive polymer with plasticizer into CaCl(2) solution. In vitro release test was carried out to investigate the release profiles in 500 ml of phosphate buffered saline (PBS, pH 7.4). As the amount of polymer in sodium alginate or coating solution increase, the drug release generally decreased. HPMC-blended microspheres swelled but withstood the disintegration, showing an ideal linear release profiles. Chitosan-coated microspheres showed smooth and round surface and extended the release of drug. In comparison with chitosan-coated microspheres, HPMC-blended alginate microspheres can be easily made and used for controlled drug delivery systems due to convenient process and controlled drug release.     

正辛胺改性海藻酸钠凝胶微球的制备及其性质研究

目的:制备正辛胺改性海藻酸钠凝胶微球,并研究其性质。方法:以超声波辅助氧化法制备多醛基海藻酸钠,通过希夫碱反应制备正辛胺改性海藻酸钠,并表征其结构;以乳化-内部凝胶化技术制备负载小分子抗肿瘤药物β-榄香烯的改性海藻酸钠凝胶微球,采用气相色谱法测定其8、15、24、48h时的累积释放率及海藻酸钠和正辛胺改性海藻酸钠凝胶微球中β-榄香烯的包封率。结果:表征并证实了多醛基海藻酸钠和正辛胺改性海藻酸钠的结构;制备得到的改性海藻酸钠凝胶微球中8、15、24、48h时β-榄香烯的累积释放率分别为16%、28%、40%、83%;海藻酸钠和正辛胺改性海藻酸钠凝胶微球中β-榄香烯的包封率分别为36%、73%。结论:制备的正辛胺改性海藻酸钠凝胶微球,具有优良的缓释性能,对β-榄香烯的包封率高。