药用丙烯酸树脂在制剂中的应用进展

目的:介绍药用丙烯酸树脂在药物制剂中应用的最新进展。方法:根据文献,以药用丙烯酸树脂中的德国商品尤特奇为代表,综述了该类辅料的理化性质及在制剂领域中的应用。结果:丙烯酸树脂根据溶解特性分为pH依赖型与pH非依赖型2种;主要用作缓控释制剂、口服定位释药系统、微球与微囊等制剂中的包衣材料及载体,可达到缓、控释或定位释放的目的,还可起到掩味、提高药物稳定性等作用。结论:丙烯酸树脂因具有多种功能和特殊性质而成为多种制剂的重要辅料,在制剂领域中具有广阔的前景。     

pH依赖型梯度释药制剂的研究进展

目的:综述pH依赖型梯度释药制剂的应用现状,为开发更符合临床应用的新型缓释制剂提供参考。方法:查阅国内外近几年来有关pH依赖型制剂的研究文献,从制剂的概念、分类、辅料和包衣技术的应用来进行详细阐述分析。结果与结论:pH依赖型梯度释药系统作为目前口服缓控释制剂的研究方向之一,主要用于结肠靶向制剂的研究,有着很好的发展前景。该剂型克服了普通制剂受肝脏首关效应的影响,依据人体的生理特点释放药物,具有能提高生物利用度、局部刺激小等优点,但给药后的定位性较差及药物在各个消化道的转运时间尚不明确,药物释放度受体内环境的影响大等,都需要药学工作者进一步的研究完善。     

药用高分子在缓控释制剂中的应用现状

<正>缓控释制剂的发展除与制药设备的不断发展、革新有关外,药用高分子在该类制剂中也是不可分割的重要组成部分。近年来,一些新型高分子材料的研究和应用使缓控释制剂步入了定时、定向、定位、速效、高效、长效的精密化给药阶段,出现了口服渗透泵控释制剂、脉冲式释药系统、环境敏感型定位释药系统、结肠定位给药系统等新型缓控释制剂。辅料的成分、组成与结构对药物的释放性能有很大的影响,因此在缓控释制剂中合理应用新型高分子材料,就具有重要的意义。1药用高分子作为药物载体药用高分子的广泛研究和应用,促进了缓控释制剂的快     

聚丙烯酸树脂类辅料在制剂中的应用

聚丙烯酸树脂是近年来应用较广泛的一类药剂新辅料，既可用作薄膜包衣材料，用于片剂、微丸、颗粒剂等剂型的包衣，又能用于缓控释制剂（如缓控释骨架片剂、微球、固体分散体等）的制备。该文对聚丙烯酸树脂的分类、性质及其在制剂中的应用情况进行了综述。     

中药缓控释制剂的研究现状

缓控释制剂是很具临床意义的一类制剂,是指药物在规定释放介质中,按要求缓慢的非恒速释放。与相应的普通制剂比较,每24小时用药次数应从3～4次减少至1～2次的制剂,它是近年来制剂研究开发的热点。本文就近年来中药缓控释制剂的研究现状综述如下。1.缓控释制剂特点减少给药次数;提高病人的依从性;降低药品的不良反应;维持持久药效。是一种能提供比较平稳血药浓度的制剂,主要应用于病程较长、需长时间用药的慢性病人,特别是肿瘤患者。2.用于缓控释制剂的辅料将药物制成任何一种剂型的制剂均必须使用一定的辅料,甚至同时需要几种辅料,因此辅料…     

多糖类药用辅料的应用及其质量分析进展

多糖由于优良的性质,在药用辅料中应用广泛,近年来成为缓控释制剂和靶向制剂载体的研究热点。多糖类辅料的质量日益引起人们关注。本文从应用和质量分析两个方面,对近年来多糖类药用辅料的研究进行综述。     

缓控释片剂的研究进展

近些年来,缓控释片剂受到了人们的广泛注意,缓控释制剂得到了突飞猛进的发展。本文通过对当今缓控释制剂、类型及相关辅料的研究进行综述,阐述当今缓控释片剂的研究现状及发展前景。     

聚乳酸-乙醇酸共聚物降解行为对缓控释制剂药物释放行为影响的研究进展

在以聚乳酸–乙醇酸共聚物（PLGA）为辅料的药物缓控释制剂中,药物的释放行为主要取决于PLGA聚合物的降解行为。PLGA的降解行为受骨架结构、环境因素和剂型因素等影响。对PLGA的降解机制进行剖析,并综述影响PLGA降解行为的相关因素,包括PLGA的单体聚乳酸与聚乙醇酸的比例、相对分子质量、pH值、结晶度、温度、药物的类型和基质包封药物后的剂型等,同时论述了其对缓控释制剂药物释放行为的影响。     

浅谈口服缓控释制剂的临床应用及注意事项

随着科学技术的发展,新辅料、新材料、新设备和新工艺的不断涌现,自20世纪70年代以来,各种新型制剂如缓控释制剂、靶向制剂脉冲式和自调式给药系统、透皮制剂等逐渐出现在临床,其中以缓控释制剂最为成熟、应用最为广泛。新型缓控释制剂的出现,不但使新技术与新剂型的研发速度加快,也使得制剂的质量与疗效得以大幅提高。     

新型缓(控)释骨架片的研究进展

缓控释片剂是口服缓、控释制剂的重要组成．加快研制和推广新剂型和新技术在口服缓控释片中的应用显得相当重要。传统的骨架片按制剂骨架材料的不同可分为不溶性骨架缓控释片、亲水凝胶骨架缓控释片、蜡质骨架缓控释片以及混合材料骨架缓控释片4种。其中。亲水凝胶骨架缓控释片可作为可溶性药物和难溶性药物的载体．是目前口服缓、控释制剂的主要类型之一．约占上市骨架片品种的60％。70％。与一般骨架片相比．新型骨架片主要是在制备工艺方面进行了改进．通过多层骨架缓控释技术、几何异型骨架技术等方式使药物实现定速、定位、定时释放的目的。以下就新型骨架缓控释技术在片剂中的应用和研究现状加以概述：     

Preparation and characterization of free mixed-film of pectin/chitosan/Eudragit RS intended for sigmoidal drug delivery.

Polyelectrolyte complex (PEC) film between pectin as an anionic polyelectrolyte and chitosan as a cationic species was prepared by blending two polymer solutions at weight ratio of 2:1 and then solvent casting method. Besides pectin/chitosan PEC film, Eudragit RS, pectin/Eudragit RS and pectin/chitosan/Eudragit RS films were also prepared by aforementioned method. In mixed-film formulations, a fixed weight ratio of 1:5 of pectin or pectin/chitosan complex to Eudragit RS was used. Characterizations of pectin/chitosan interaction in solution were investigated by turbidity and viscosity measurement and in the solid state by Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXRD) and thermogravimetric analysis (TGA). It was observed that the swelling profile of pectin/chitosan film was pH-dependent and its swelling ratio in phosphate buffer solution (PBS) pH 7.4 was about 2.5-fold higher than that of PBS pH 6.0. Formulation containing only pectin/chitosan could not protect free film from high swelling in the aqueous media, therefore, Eudragit RS as a water-insoluble polymer must be included in the mixed-film. The formation of PEC between pectin and chitosan resulted in a decrease in the crystallinity and thermal stability caused by the interactions between polyions. Drug permeation or diffusion studies were carried out using Plexiglas diffusion cell consisting of donor and acceptor compartments. Theophylline was selected as a model drug to measure permeability coefficient. Drug permeation through pectin/chitosan/Eudragit RS showed a sigmoidal pattern; whereas drug diffusion through pectin/Eudragit RS and Eudragit RS films followed a linear characteristic. The drug permeation through the ternary mixed-film showed a burst release upon exposure to PBS pH 6.0. This mixed-film formulation showed the potential for sigmoidal drug delivery with an initial, controllable slow release followed by a burst release immediately after the change in pH. The burst drug permeation might possibly be due to change in film's porosity.     

5-氟尿嘧啶结肠定位释药微丸的研制及释药特性

采用流化床喷雾包衣法,研制了2种5-氟尿嘧啶结肠定位释药微丸.以羟丙甲纤维素为溶胀层,乙基纤维素水分散体为控制层,制备时间依赖型包衣微丸;另以肠溶型丙烯酸树脂Eudragit S100为包衣材料,制备pH依赖型微丸.测定了2种微丸在模拟胃肠道各区段pH环境下的释放度.结果表明,时间依赖型包衣微丸体外持续、缓慢释放;pH依赖型包衣微丸在模拟胃和小肠中上部pH的介质中基本不释药,在模拟回盲部区段pH介质中脉冲释药,即后者在体外显示出较好的结肠定位释药特性.     

Combination of time-dependent and pH-dependent polymethacrylates as a single coating formulation for colonic delivery of indomethacin pellets

The objective of this study was to evaluate the combination of pH-dependent and time-dependent polymers as a single coating for design of colon delivery system of indomethacin pellets. Eudragit S100 and Eudragit L100 were used as pH-dependent polymers and Eudragit RS was used as a time-dependent polymer. A statistical full factorial design was used in order to optimize formulations. Factors studied in design were percent of Eudragit RS in combination with Eudragit S and L and coating level. Dissolution studies of pellets in the media with different pH (1.2, 6.5, 6.8 and 7.2) showed that drug release in colon could be controlled by addition of Eudragit RS to the pH-dependent polymers. The lag time prior to drug release was highly affected by coating level. With combination of two factors, i.e. the percent of Eudragit RS and coating level, the optimum formulation was found to be the one containing 20% Eudragit RS, 64% Eudragit S and 16% Eudragit L, and a coating level of 10%. This formulation was reproduced and tested in continuous condition of dissolution, and also separately at pH 7.5. The results of in vitro experiments indicate that the proposed combined time-dependent and pH-dependent polymethacrylate polymer coating may provide a colonic delivery system for indomethacin.     

Dissolution characteristics of composite particles using a spray freeze drying

A spray freeze drying (SFD) method, using a spray nozzle, liquid N(2) and a lyophilizer, was developed to prepare composite particles of a poorly water-soluble drug. The resultant particles were found to have a porous structure. The purpose of the present research was to prepare a sustained release formulation using the SFD technique. Tolbutamide (TBM)and Eudragit S were used as model drugs and pH-dependent carrier, respectively. Eudragit S is a polymer that is soluble at or above pH 7.0. Morphological evaluation of the composite particles revealed that they had a porous structure with a significantly larger specific surface area than bulk TBM. The physicochemical properties of the particles were found to be dependent on the drug to carrier ratio, with the crystallinity of the TBM decreasing as the proportion of Eudragit S increased. Dissolution tests in solutions of pH 1.2 and pH 6.8 showed that the release profiles of TBM from the SFD composite particles were improved compared to bulk TBM, through the use of the pH-dependent carrier. On the other hand, following compression of the composite particles, sustained release was observed in a solution of pH 6.8, whereas almost no dissolution occurred in a solution of pH 1.2.     

法莫替丁定时释放小丸的释药机制

目的研究法莫替丁定时释放小丸的释药机制,初步探索有机酸诱导型给药系统的释药机制。方法从离子交换反应、水化作用等方面分别研究了琥珀酸离子和琥珀酸分子在药物释放过程中的作用。结果琥珀酸酸根离子通过与膜材进行离子交换反应造成了新的离子环境,琥珀酸分子由于进入膜材的疏水部分而提高了膜的柔韧性。上述两种作用均可导致膜水化作用增强,从而使膜的透过性明显增加。结论定时释放小丸的时滞是由于膜材的疏水性所致;当水进入丸芯溶解有机酸后,产生的酸根离子及有机酸分子以不同的方式与膜材发生相互作用,显著提高了其透过性,从而使药物快速释放出来。     

Permeability and swelling studies on free films containing inulin in combination with different polymethacrylates aimed for colonic drug delivery.

The aim of this study was to assess some permeability and swelling characteristics of free films prepared by combination of inulin as a bacterially degradable system and time- or pH-dependent polymers as a coating formulation for colonic drug delivery. Different free films were prepared by casting and solvent evaporation method. Formulations containing inulin with Eudragit RS, Eudragit RL, Eudragit RS-Eudragit RL, Eudragit FS and Eudragit RS-Eudragit S with different ratios of inulin were prepared. After preparation, free films were evaluated by water vapor transmission test, swelling experiment and permeability to indomethacin and theophylline in different media. Formulations containing Eudragit FS had high resistance to water vapor permeation; but were unable to protect premature swelling and drug release in simulated small intestine media. Also, combination of Eudragit RS and Eudragit S had no suitable characteristics for colon delivery. However, Eudragit RS and Eudragit RL in combination with inulin made free films which had more swelling and permeation of drug in the colonic medium rather than the other media. It was shown that formulations containing sustained release polymethacrylates in combination with inulin have more potential as a coating system for specific colon delivery compared with pH-dependent polymers.     

Relationship of film properties to drug release from monolithic films containing adjuvants.

The rate of drug release from a polymeric matrix system was influenced by the physical and chemical properties of the monolithic films. The model drugs, salicylic acid and chlorpheniramine maleate, and two poly(methyl methacrylate) copolymers of different permeabilities (Eudragit RL and Eudragit RS), with and without additional adjuvants, were used to form monolithic matrix films for controlled drug release. Adjuvants, including polyethylene glycols (PEG 400 and PEG 8000) and poly(vinylpyrrolidones) (PVP-K15 and PVP-K90), were incorporated into films of Eudragit RL PM and Eudragit RS PM. The moisture permeation constant, glass transition temperature (Tg), tensile strength, and drug release profiles were determined for each acrylic resin slab to correlate the physicochemical and physicomechanical film properties to observed drug release. Faster rates of drug diffusion were observed with the addition of PEG 400 to the films, because of its plasticizing effect and the resultant increased moisture permeability of the matrix. An exception existed with the Eudragit RL PM film containing salicylic acid where drug-polymer interactions inhibited drug diffusion. The small changes in moisture permeability, Tg, and tensile strength observed with incorporation of the PVPs had an insignificant influence on the dissolution results for salicylic acid from Eudragit RS PM films. Increases in the tensile strength and Tg after addition of PVP to the Eudragit RS PM matrix support the observed decreased rate of diffusion for chlorpheniramine maleate. The pores formed by migration of the hydrophilic adjuvants from the films altered the diffusion kinetics of the matrix, compared with that of the nonporous polymer, when only the antihistamine was present.     

Influence of formulation and process variables on in vitro release of theophylline from directly-compressed Eudragit matrix tablets

Extended-release theophylline (TP) matrix tablets were prepared by direct compression of drug and different pH-dependent (Eudragit L100, S100 and L100-55) and pH-independent (Eudragit RLPO and RSPO) polymer combinations. The influence of varying the polymer/polymer (w/w) ratio and the drug incorporation method (simple blend or solid dispersion) was also evaluated. Drug release, monitored using the Through Flow Cell system, markedly depended on both the kind of Eudragit polymer combinations used and their relative content in the matrix. Maintaining a constant 1:1 (w/w) drug/polymers ratio, the selection of appropriate mixtures of pH-dependent and pH-independent polymers enabled achievement of a suitable control of TP release. In particular, matrices with a 0.7:0.3 w/w mixture of Eudragit L100-Eudragit RLPO showed highly reproducible drug release profiles, with an almost zero-order kinetic, and allowed 100% released drug after 360 min. As for the effect of the drug incorporation method, simple blending was better than the solid dispersion technique, which not only did not improve the release data reproducibility, but also caused, unexpectedly, a marked slowing down in drug release rate.     

Electrospun diclofenac sodium loaded Eudragit® L 100-55 nanofibers for colon-targeted drug delivery

Eudragit? L 100-55 nanofibers loaded with diclofenac sodium (DS) were successfully prepared using an electrospinning process, and characterized for structural and pharmacodynamic properties. The influence of solvent and drug content on fiber formation and quality was also investigated. Fiber formation was successful using a solvent mixture 5:1 (v/v) ethanol:DMAc. XRD and DSC analysis of fibers confirm electron microscopic evidence that DS is evenly distributed in the nanofibers in an amorphous state. FTIR analysis indicates hydrogen bonding occurs between the drug and the polymer, which accounts for the molecular integration of the two components. In vitro dissolution tests verified that all the drug-loaded Eudragit? L 100-55 nanofibers had pH-dependent drug release profiles, with limited, less than 3%, release at pH 1.0, but a sustained and complete release at pH 6.8. This profile of properties indicates drug-loaded Eudragit? L 100-55 nanofibers have the potential to be developed as oral colon-targeted drug delivery systems.     

Influence of an enteric polymer on drug release rates of theophylline from pellets coated with Eudragit RS 30D

The purpose of this research study was to investigate the influence of an enteric polymer on the drug release properties of theophylline pellets coated with Eudragit RS 30D. Theophylline pellets were coated with aqueous colloidal dispersions of Eudragit RS 30D containing various amounts of Eudragit L 100-55. The effect of storage conditions on the release of drug from coated pellets was determined as a function of the pH of the dissolution medium. The results from the dissolution study showed significant changes in the dissolution rate of theophylline from pellets coated with Eudragit RS 30D when cured at 40 degrees C for 4 days. No change in the drug release rate was observed when Eudragit L100-55 was present in the Eudragit RS 30D dispersion. Increasing the ratio of Eudragit L100-55 to Eudragit RS 30D resulted in faster drug release rates from the coated pellets. An increase in the pH of the dissolution medium was found to enhance drug release from the pellets coated with Eudragit RS 30D containing Eudragit L 100-55. Theophylline pellets when coated with Eudragit RS 30D containing the enteric polymer Eudragit L100-55 demonstrated no aging effects when stored at elevated temperatures. The overcoating of the pellets with Eudragit RD 100 did not affect the drug release profiles and prevented the particles from agglomerating during curing and storage.