延胡索乙素固体脂质纳米粒缓释片制备及工艺优化

目的：制备延胡索乙素固体脂质纳米粒缓释片，并研究延胡索乙素固体脂质纳米粒缓释片的释药模型和释药机理。方法：乳化-溶剂挥发法制备延胡索乙素固体脂质纳米粒，以乳糖作为冻干剂，羟丙基甲基纤维素（HPMC）为缓释材料进一步制备缓释片。在单因素考察的基础上，设计正交试验优化延胡索乙素固体脂质纳米粒缓释片处方，并对缓释片体外释药模型和释药机理进行探讨。结果：延胡索乙素固体脂质纳米粒缓释片最佳处方为缓释材料HPMC K4M和HPMC K15M比例为1：1，用量为40 mg，PEG 4000的用量为20 mg，硬脂酸镁用量为片芯质量的0.5%。延胡索乙素固体脂质纳米粒缓释片最佳处方的体外释放行为符合Higuchi释药模型，释药方程为：Mt/M_∞=0.286 8 t^1/2-0.073 8（r=0.990 8），12 h内累积释放度为93.56%，缓释片释药机理为扩散和溶蚀共存。结论：制备的延胡索乙素固体脂质纳米粒缓释片，工艺重复性较好，其释药行为符合Higuchi释药模型。     

愈创甘油醚缓释片的研究

目的 研究1天给药2次的愈创甘油醚骨架型缓释片。方法 以HPMC为骨架材料，采用正交试验设计，考察HPMC的不同型号和不同用量对释放度的影响，筛选出最佳处方。结果体外释放度实验表明，缓释片比普通片释药时间延长，其体外释放行为符合Higuclli(r=0．9915)方程。结论 该缓释片处方工艺简单，适合工业化生产；缓释效果明显。     

布洛芬缓释滴丸的处方工艺优化及体外释药行为评价

目的:优化布洛芬缓释滴丸的处方工艺并评价其体外释药特征。方法:以硬脂酸为缓释基质、聚乙二醇6000为速释基质,采用熔融法制备布洛芬缓释滴丸。以圆整度、丸重差异、载药率、体外释药时间的综合评分为指标,以药物与基质质量比、药液温度、冷凝温度、滴距为因素,通过正交试验优化处方工艺并验证。在去离子水、盐酸溶液(pH 1.2)、磷酸盐缓冲液(pH 4.5、6.8)4种介质中,比较自制缓释滴丸与市售布洛芬缓释胶囊的体外释药行为,并对前者的释药行为进行拟合。结果:最优处方工艺为布洛芬-聚乙二醇6000-硬脂酸的质量比为4.0∶15.3∶0.7,药液温度为83℃,冷凝温度为8℃,滴距为11 cm;所制3批布洛芬缓释滴丸的丸重差异为2.067%、圆整度为96.73%、载药率为96.31%、12 h的累积释放度为93.05%,RSD分别为1.19%、0.28%、0.19%、0.81%。自制缓释滴丸与市售布洛芬缓释胶囊体外释药行为的相似因子f2均大于50,前者释药更符合Higuchi方程(r为0.988 1~0.997 2)。结论:成功优化布洛芬缓释滴丸的处方工艺,所制缓释滴丸的体外释药行为与市售布洛芬缓释胶囊相似。     

右旋布洛芬缓释栓的制备工艺及其体外释放特性研究

目的 制备右旋布洛芬缓释栓,评价其体外释放特性。方法 用正交实验设计,对右旋布洛芬缓释栓的处方和工艺进行筛选与优化,用筛选的最佳处方制备右旋布洛芬缓释栓,测定其体外释放特性。结果 以优选的处方和工艺制备的栓剂,体外释药性能良好,符合Higuchi模型,体外释药能持续＞8 h。结论 该处方设计合理,制剂制备工艺可行,质量控制方法可靠。     

曲尼司特缓释片的制备及其释药影响因素研究

目的　制备了曲尼司特凝胶骨架片。方法　采用HPMCK4M、K15M为凝胶骨架材料 ,进行了处方研究 ;通过测定制剂体外释放度 ,评价了该缓释片处方。结果　曲尼司特缓释片体外释药符合Higuchi方程 ,其释药速率常数Kr为 0 193h-1/ 2 。影响缓释片体外释药的因素有骨架材料的种类、用量、粘合剂的种类和释药介质的pH等。结论　缓释片具有明显的缓释作用 ,可缓慢释药 12h。     

曲尼司特缓释片的制备及其释药影响因素研究

目的 制备了曲尼司特凝胶骨架片。方法 采用HPMC K4M、K15M为凝胶骨架材料，进行了处方研究；通过测定制剂体外释放度，评价了该缓释片处方。结果 曲尼司特缓释片体外释药符合Higuchi方程，其释药速率常数Kr为0．193h^1/2。影响缓释片体外释药的因素有骨架材料的种类、用量、粘合剂的种类和释药介质的pH等。结论 缓释片具有明显的缓释作用，可缓慢释药12h。     

非普拉宗缓释片的制备及体外释放度的研究

目的：研制凝胶骨架型非普拉宗缓释片，考查缓释片的体外释药特性。方法：以羟丙甲基纤维素（HPMC）作为主要凝胶材料，采用正交试验法，根据体外释放速率优选处方。结果：缓释片在16h内缓慢释药，其体外释药速率符合一级动力学方程。结论：释药速度主要受HPMC的类型和用量的影响，但受压片的压力影响较小。     

氢溴酸右美沙芬缓释片的制备及释放度研究

研究氢溴酸右美沙芬（DMB）凝胶骨架缓释片的制备和体外释放特性。方法：以羟丙基甲基纤维素（HPM）、已基纤维素（EC）和乳糖（Lactose）为辅料,采用均匀设计方法优化处方研制成氢溴酸右美沙芬凝胶骨架片,并研究了制片压力、释药介质的pH值、稀释剂的性质、辅料的粘度和用量等因素对DMB缓释片释药特性的影响。结果：经处方优化研制出的DMB缓释片8h体外释药90％左右,其释药曲线符合Miguchi动力学模型,不同时间的释放参数分别为t0．5＝2．8h,t0．9＝8．02h。结论：氢溴酸右美沙芬适合制成凝胶骨架缓释片,其释药速率随稀释刑或阻滞剂的用量而改变。     

盐酸青藤碱缓释微丸的研制

目的：制备盐酸青藤碱缓释微丸，并对其体外释药行为进行研究。方法：采用离心造粒技术制备盐酸青藤碱素丸，在流化床内采用丙烯酸树脂水分散体对其包衣，制备盐酸青藤碱缓释微丸。对包衣材料种类、配比及用量进行选择，对包衣微丸体外释药机理进行研究。结果：包衣材料Eudragit NE30D增重5％时，包衣微丸在水中呈现良好的缓释效果，体外释药过程基本符合Higuchi方程：Y=0．0938＋0．0846t（r=0．9965）。结论：采用离心造粒技术和丙烯酸树脂流化床包衣，成功地制备了盐酸青藤碱缓释微丸，其体外释药缓慢、平稳。     

头孢拉定缓释片制备及体外释药的影响因素

目的：提供头孢拉定亲水凝胶缓释片的制备方法，考察影响体外累积释放率的各种相关因素。方法：采用羟丙基甲基纤维素(HPMC)为缓释材料制备头孢拉定亲水凝胶缓释片，以及HPMC的用量、黏度、压力等因素对头孢拉定缓释片体外累积释放率的影响。结果与讨论：本实验制备的头孢拉定缓释片体外释药测定结果表明符合Higuchi方程，线性回归系数0．9969，HPMC的用量以及黏度对头孢拉定缓释片的释药速率有显著影响，释药速率随HPMC用量的增加或黏度的加大而明显减慢，硬度在600～900kPa范围内时对释药速率的影响不明显。     

Formulation and evaluation of a sustained-release tablets of metformin hydrochloride using hydrophilic synthetic and hydrophobic natural polymers

Metformin hydrochloride has relatively short plasma half-life, low absolute bioavailability. The need for the administration two to three times a day when larger doses are required can decrease patient compliance. Sustained release formulation that would maintain plasma level for 8-12 h might be sufficient for daily dosing of metformin. Sustained release products are needed for metformin to prolong its duration of action and to improve patient compliances. The overall objective of this study was to develop an oral sustained release metformin hydrochloride tablet by using hydrophilic Eudragit RSPO alone or its combination with hydrophobic natural polymers Gum copal and gum damar as rate controlling factor. The tablets were prepared by wet granulation method. The in vitro dissolution study was carried out using USP 22 apparatus I, paddle method and the data was analysed using zero order, first order, Higuchi, Korsmeyer and Hixson-Crowell equations. The drug release study revealed that Eudragit RSPO alone was unable to sustain the drug release. Combining Eudragit with gum Copal and gum Damar sustained the drug release for more than 12 h. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled or Fickian transport to anomalous type or non-Fickian transport. Fitting the in vitro drug release data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release.     

The effect of tablet formulation and hardness on in vitro release of cephalexin from Eudragit L100 based extended release tablets

Eighteen batches of cephalexin extended release tablet were prepared by wet granulation method by using Eudragit L100. The effect of the concentration of Eudragit L100, microcrystalline cellulose and tablet hardness on cephalexin release was studied. The formulated tablets were also characterized for physical and chemical parameters. The dissolution results showed that a higher amount of Eudragit in tablet composition and higher tablet hardness resulted in reduced drug release. An increased amount of microcrystalline cellulose in tablet composition resulted in enhanced drug release. Tablet composition of 13.3% w/w Eudragit L100 and 6.6 to 8% w/w microcrystalline cellulose with hardness of 7-11 kg/cm2 gave predicted release for 6 h. The in vitro release was compared with a marketed tablet. Physical and chemical parameters of all formulated tablets were within acceptable limits. The effect of storage on in vitro release and physicochemical parameters of tablets was evaluated and two batches among formulated eighteen batches found to be in acceptable limits.     

银杏叶提取物微丸的制备及其释放度研究

目的:制备银杏叶提取物微丸,并测定其体外释放度。方法:采用3种不同包衣材料(欧巴代Ⅱ、Eudragit L30D-55、Eu-dragit S100)对银杏叶提取物进行包衣,采用离心造粒法制备成相应的包衣微丸;将3种包衣微丸按预设比例混合制成混合包衣微丸;采用pH梯度改变介质方式(0.1mol.L-1盐酸、pH5.8PBS、pH7.2PBS)测定包衣微丸和混合包衣微丸的释放度。结果:3种不同包衣微丸分别在0.1mol.L-1盐酸、pH5.8PBS、pH7.2PBS中可以迅速释放;混合包衣微丸在pH梯度改变介质中持续释放,约8h释放完全。结论:该制备工艺可行,可为工业化生产提供理论依据。     

Preparation and characterization of ibuprofen microspheres

Ibuprofen was microencapsulated with Eudragit RS using an o/w emulsion solvent evaporation technique. The effects of three formulation variables including the drug:polymer ratio, emulsifier (polyvinyl alcohol) concentration and organic solvent (chloroform) volume on the entrapment efficiency and microspheres size distribution were examined. The drug release rate from prepared microspheres and the release kinetics were also studied. The results demonstrated that microspheres with good range of particle size can be prepared, depending on the formulation components. The drug:polymer ratio had a considerable effect on the entrapment efficiency. However, particle size distribution of microspheres was more dependent on the volume of chloroform and polyvinyl alcohol concentration rather than the drug:polymer ratio. The drug release pattern showed a burst effect for all prepared microspheres due to the presence of uncovered drug crystals on the surface. It was shown that the release profiles of all formulations showed good correlation with the Higuchi model of release.     

Preparation and characterization of ibuprofen microspheres

Ibuprofen was microencapsulated with Eudragit RS using an o/w emulsion solvent evaporation technique. The effects of three formulation variables including the drug:polymer ratio, emulsifier (polyvinyl alcohol) concentration and organic solvent (chloroform) volume on the entrapment efficiency and microspheres size distribution were examined. The drug release rate from prepared microspheres and the release kinetics were also studied. The results demonstrated that microspheres with good range of particle size can be prepared, depending on the formulation components. The drug:polymer ratio had a considerable effect on the entrapment efficiency. However, particle size distribution of microspheres was more dependent on the volume of chloroform and polyvinyl alcohol concentration rather than the drug:polymer ratio. The drug release pattern showed a burst effect for all prepared microspheres due to the presence of uncovered drug crystals on the surface. It was shown that the release profiles of all formulations showed good correlation with the Higuchi model of release.     

布洛芬缓释干混悬剂的制备及大鼠体内药代动学研究

目的 制备布洛芬口服缓释干混悬剂,以期为一些吞咽困难的患者提供自主给药、方便的新剂型.方法 采用湿法制粒技术制备含药微粒,分别以累积释放度、沉降体积比和再分散性为评价指标筛选缓释载体种类及比例、助悬剂种类及用量,制备布洛芬口服缓释干混悬剂,并对其大鼠体内药动学进行研究.结果 布洛芬(ibuprofen,IBU)缓释干混...     

Novel time and site specific “tablets in capsule” system for nocturnal asthma treatment

The objective of present work was to develop a “tablets in capsule” system for facilitating both immediate and pulsatile drug deliveries of theophylline to mimic the circadian rhythm of nocturnal asthma. The system comprised of capsule filled with two tablets, first pulse and second pulse tablet prepared by wet granulation method. First pulse tablet was not coated and was responsible for providing loading dose whereas; second pulse tablet was coated with Eudragit L100 and Eudragit S100 to release drug in colon after specific lag time. Two independent variables, amount of polymers and coating thickness, were optimized by 3² full factorial design. The optimum formulation consisted of Eudragit L100: Eudragit S100 in 1:1.5 ratio and coating thickness of 20 % (w/w). In vitro drug release of “tablets in capsule” system in three different media (pH 1.2, pH 6.8, and pH 7.4) revealed immediate and pulsatile release patterns.     

Design and evaluation of sustained release microspheres of potassium chloride prepared by Eudragit.

The aim of the present work was to prepare and evaluate the sustained release of potassium chloride formulations. Eudragit RS and/or RL loaded with potassium chloride microspheres were prepared by a solvent evaporation method. The effect of sustained release of Eudragit microspheres was evaluated by an in vitro dissolution test and in vivo oral absorption study, and the results were compared to a commercial product (Slow-K). The results showed that Eudragit microspheres loaded with potassium chloride can be easily prepared and satisfactory results obtained considering the size distribution and shapes of microspheres by incorporating aluminum stearate. The encapsulation efficiency and loading capacity were about 84-90% and 27%, respectively. Moreover, the Eudragit RS (30-45 mesh) and Eudragit RS/RL (20-30 mesh) microspheres showed a similar sustained release effect of commercial product via in vitro dissolution and in vivo oral absorption study.     

Design and study of ibuprofen disintegrating sustained-release tablets comprising coated pellets.

One challenge in tableting of sustained-release multiparticulates is maintaining the desired drug release after compaction. The aim of this study was to design sustained-release ibuprofen tablets which upon oral ingestion rapidly disintegrate into sustained-release pellets in which the integrity of the pellet core and/or coat is preserved. First free films composed of Eudragit RS 30D and RL 30D in 4:1 ratio and containing different levels of triethyl citrate (TEC) were prepared and tested to optimize the plasticizer level. Cured Eudragit based pellets with 60% ibuprofen loading which in our previous study showed proper mechanical properties for compression were coated with Eudragit RS 30D/RL 30D (4:1) containing 20% triethyl citrate at different coating levels. The mechanical properties of the coated pellets were tested. Polymer coated pellets were compacted into tablets either alone or with a blend of excipients comprising Avicel, PEG 4000, cross-linked PVP. A 3(2) full factorial design was used to optimize the filler blend composition. Effects of pellet to filler ratio, compression force and granulation of filler on tablet characteristics were investigated. Results of mechanical test showed that the coating of cured pellets had no significant effect on yield point and elastic modulus of the pellets. In the case of 5% coating level sustained release of ibuprofen over a period of 24h was achieved. The results obtained from tableting procedure showed that by selecting suitable filler blend (60% Avicel, 10% cross-linked PVP and 30% PEG 4000), compression force, and granulation of filler it was possible to prepare sustained-release tablets containing high ratio of coated pellets (even 80%) with desirable strength, disintegration time, and drug release rate. It was observed that compression force, pellet to filler ratio, composition of filler blend and granulation of fillers had no effect on drug release rate from compacted pellets but had significant influence on tablet strength, friability, and disintegration time. SEM graphs and in vitro release profiles for compacted pellets showed no apparent damage to the coated pellets as a result of the compaction process.     

Physical characterization and dissolution properties of ibuprofen: Eudragit coprecipitates.

Ibuprofen:Eudragit coprecipitates were prepared in 10:3 ratios and their physical properties and related dissolution characteristics were determined. The Eudragit polymers used for the studies were three anionics (Eudragit L100, Eudragit L100-55, and Eudragit S-100), one anionic:cationic mixture used in a 1:1 ratio (Eudragit S100 + E100), and four zwitterionics (Eudragits RL 100, RS 100, RSPM, and RLPM). Physical characterizations were made using qualitative and quantitative X-ray diffractometry, IR spectrophotometry, and differential scanning calorimetry (DSC). Except for Eudragit S100 + E100 coprecipitates, no sizeable interaction at a molecular level was detected between the drug and the polymer. The crystalline structure of the drug was slightly modified in the coprecipitates. Regardless of the lack of interaction, dissolution of ibuprofen was retarded from all the coprecipitates studied (except Eudragit L100), especially in the pH 6.8 to 7.5 media in which the drug is freely soluble. The dissolution rate constants of the coprecipitates, calculated using Higuchi equation, demonstrated that dissolution decreased in the order of anionics greater than zwitterionic greater than anionic + cationic mixtures. The data obtained suggest that the release mechanisms involved are the swelling and slower dissolution of the polymer matrix relative to precipitated ibuprofen. The coprecipitates possess improved flow properties compared with ibuprofen with the exception of Eudragit RLPM and Eudragit RSPM. Eudragit coprecipitates can be useful tools in preparing ibuprofen sustained-release tablets. The coprecipitation technique used is simple and minimizes the use of organic solvents.