洛索洛芬钠双层缓释片的研制和体外释放特性研究

目的：研制洛索洛芬钠双层缓释片并考察其体外释药特性。方法：以两种不同处方作湿法制粒,压制双层片,用高效液相色谱法测定洛索洛芬钠的释放度.结果与结论：洛索洛芬钠双层缓释片的释药曲线可用Higuchi方程或Peppas方程拟合,可维持12h持续释放达到设计要求.     

法莫替丁生物黏附缓释片释放机制研究

目的探讨法莫替丁生物黏附缓释片的释药机制及影响因素。方法以羟丙基甲基纤维素（HPMC）为骨架材料，卡波姆为生物黏附材料，乳糖为辅料制备生物黏附缓释片，运用Ritger-Peppas方程释放指数n值，评价HPMC、卡波姆和乳糖对释药速率的影响。结果生物黏附片的释药速率随HPMC、卡波姆含量增高而减慢，乳糖可以加快释药速率，经处方筛选优化后制备的法莫替丁生物黏附缓释片的释放，是Fick扩散和凝胶骨架溶蚀两种机制的协同作用结果。结论HPMC、卡波姆和乳糖均可影响法莫替丁生物黏附片中主药的释放，生物黏附缓释片的释药过程可用Ritger—Peppas方程进行描述。     

卡维地洛凝胶骨架缓释片的处方优选与表征

目的 优选12 h内体外缓慢释药的卡维地洛凝胶骨架缓释片的处方工艺并进行表征。方法 以2种型号的HPMC为骨架材料,通过正交试验法,优选处方工艺并验证,考察制剂在4种介质中12 h内的体外释放度,利用X-射线衍射法和红外光谱法分析药物的存在状态。结果 最佳处方为卡维地洛7.5%,单硬脂酸甘油酯30%,HPMC K4M+E50占片重25%,HPMC K4M∶E50的比例为2∶1,乳糖占15%,硬度为3.5 kg;制剂在pH 1.2的介质中释药最快,12 h内达到90%以上,体外释药稳定（RSD<1.5%,n=3）,符合Higuchi动力学方程,属于骨架溶蚀型释药系统;药物在片中以部分晶体存在,原辅料之间没有新键生成。结论 该制备工艺简单,重复性良好,在12 h内具有良好的体外缓释特征。     

阿昔洛韦缓释片在不同介质中的释放研究

目的:研究阿昔洛韦缓释片在不同介质中的体外释药特性。方法:以转篮法进行溶出度研究;采用紫外分光光度法在254nm波长下测定阿昔洛韦缓释片在4种释放介质即0.1mol·L-1盐酸液、pH6.8磷酸盐缓冲液、蒸馏水和由0.1mol·L-1盐酸液(前2h)与pH6.8磷酸盐缓冲液(2h后)组成的替换介质中的12h内的释放度,并进行释放行为模型的拟合。结果:阿昔洛韦缓释片在盐酸液中的释放速度最快,但12h时4种介质中阿昔洛韦皆释放完全;阿昔洛韦在4种介质中体外释药拟合模型更接近Higu-chi方程和Peppas方程。结论:阿昔洛韦缓释片在不同介质中均具有缓释性,释放机制主要为扩散释药。     

Diffusion in HPMC Gels. II. Prediction of Drug Release Rates from Hydrophilic Matrix Extended-Release Dosage Forms

Purpose. A mathematical model is described for the prediction of the relative change in drug release rate as a function of formulation composition for HPMC-based extended-release (ER) tablets of adinazolam mesylate and alprazolam. Methods. The model is based on the equation derived by Higuchi for the diffusional release of soluble drugs from polymeric matrices and on our recent measurements of the concentration dependency of adinazolam diffusivity in dilute HPMC gels and solutions. The assumptions made in applying the model include (i) that diffusion is the sole mechanism of drug release (i.e. swelling kinetics are ignored), and (ii) that the surface area-to-volume ratio and concentrations of adinazolam, lactose and HPMC in the gel layer are proportional to that of the dry tablet. Results. Reasonable correlations were obtained between the experimental drug release rate ratios and the predicted drug release rate ratios for ER adinazolam mesylate (R² = 0.82) and low-dose (0.5 mg) ER alprazolam tablets (R² = 0.87). The predictive power for a 6-fold higher dose of ER alprazolam tablets was not as good (R² = 0.52). Conclusions. These results are consistent with previous knowledge of the release mechanisms of these formulations. ER adinazolam mesylate and ER alprazolam 0.5 mg exhibit primarily a diffusion controlled release mechanism, while ER alprazolam 3 mg deviates from pure diffusional release. The limitations of the model are discussed and point to the need for continued study of the swelling kinetics of matrix ER systems.     

Formulation and in Vitro-in Vivo Evaluation of Sustained-Release Lithium Carbonate Tablets

The release of lithium carbonate incorporated into polymethylmethacrylate, poly vinyl chloride, hy-drogenated vegetable oil, and carbomer matrix tablets was studied in vitro. The formulation containing 10% carbomer showed a sustained-release profile comparable to that of a standard, commercially available, sustained-release preparation containing 400 mg lithium carbonate embedded in a composite material. In vivo the newly formulated and standard sustained-release lithium carbonate tablets were compared to an oral solution and conventional lithium carbonate tablets in 12 healthy subjects. These crossover studies showed that the sustained-release tablets produced a flatter serum concentration curve than the oral solution and conventional tablet, without loss of total bioavailability.     

硫普罗宁缓释片的制备及体外释放度考察

目的制备硫普罗宁缓释片并对其体外释放度进行考察。方法以HPLC法为分析方法,采用相似因子法评价硫普罗宁缓释片体外释放行为。结果硫普罗宁缓释片的体外释放行为符合Highuchi方程。KollidonSR用量、填充剂的种类与用量及种类对药物的释放速度有较大影响,而硬度和释放介质的离子强度对药物的释放速度无显著影响。结论体外释放度符合缓释制剂要求,可进一步进行体内释药行为考察。     

美乐托宁缓释片在不同介质中的释放试验

目的:制备美乐托宁缓释片,以国外上市制剂美乐托宁缓释片为参比制剂,考察自研制剂和参比制剂在不同pH释放介质中体外释放行为的相似性及体外释药机制。方法:采用释放度测定法转篮法的装置进行体外释放实验,用HPLC法测定释放度,采用f2相似因子对2种制剂释放曲线的相似度进行评价,并进行释放行为模型的拟合。结果:在不同pH的释放介质中,自制制剂释放度曲线与参比制剂比较,f2相似因子均大于50;美乐托宁缓释片在4种释放介质中体外释药拟合模型更接近一级方程、Higuchi方程和Peppas方程。结论:参比制剂与自制制剂在不同pH释放介质中的体外释放一致,释放机制为扩散释药。     

法莫替丁生物黏附缓释片的体外释放研究

目的:评价法莫替丁生物黏附缓释片的体外释放特性。方法:建立法莫替丁生物黏附缓释片释放度的高效液相色谱测定法,运用Higuchi方程、Ritger-Peppas方程拟合其释放过程,采用Peppas修正式分析释放过程中不同机制的释药比例。结果:Ritger-Peppas方程更能拟合法莫替丁生物黏附缓释片的释放,凝胶骨架溶蚀机制在法莫替丁生物黏附缓释片的释放评价中占有更重要的地位。结论:Peas修正式可定量评价法莫替丁生物黏附缓释片的体外释放。     

藤甲酰苷缓释片的处方优化及释药机制研究

目的：制备藤甲酰苷缓释片并探讨其药物释放机理。方法：以羟丙基甲基纤维素（HPMC）为缓释材料、乙基纤维素（EC）为凝胶骨架材料,以及乳糖等为填充剂制备藤甲酰苷缓释片,采用正交设计法进行处方优化。使用DDslover软件拟合释放曲线。结果：采用压片法制得的骨架型藤甲酰苷缓释片具有良好的缓释效果。藤甲酰苷缓释片的体外释药行为符合 Higuchi 模型,是扩散和溶蚀协同作用的结果,其释药过程用 Higuchi 平面扩散模式方程,相关系数 r = 0.9993（1～12小时）。结论：制备出体外释放度符合要求的藤甲酰苷缓释片。     

卡维地洛缓释片的制备及其释放度考察

目的 制备卡维地洛缓释片并考察其体外释放度.方法 采用粉末直接压片法制备卡维地洛缓释片,紫外分光光度法测定卡维地洛的含量,考察其在体外的释放度.结果 所制备卡维地洛缓释片4h内药物累积释放量为40％左右,体外释放曲线拟合优度较好的方程为Higuchi方程,相关系数为r=0.993 7.结论 卡维地洛缓释片中药物释放具有明显的缓释效果.     

Pharmacokinetic and Pharmacodynamic Comparison of Immediate-Release and Sustained-Release Adinazolam Mesylate Tablets After Single- and Multiple-Dose Administration

The effect of adinazolam release rate on psychomotor performance and sedation was assessed by administering 40 mg adinazolam mesylate immediate-release (CT) tablets, 60 mg sustained-release (SR) tablets, and placebo in a double-blind crossover study in 15 healthy male subjects. A separate panel of 16 subjects received the above single doses and multiple-dose regimens of 40 mg CT tablets every 8 hr and 60 mg SR tablets every 12 hr according to a crossover design. Psychomotor performance was assessed by digit symbol substitution test, card sorting tasks, and sedation ratings. Following single-dose administration, dose-corrected adinazolam and N-desmethyladinazolam (NDMAD) AUC values were equivalent for SR and CT tablets. Peak adinazolam and NDMAD levels were lower and occurred later for the SR tablets. Decrements in card sorting were 50 and 3% at 1 hr and 17 and 20% at 6 hr for the CT and SR tablets, respectively. Maximal sedation scores were lower for the SR tablets compared to the CT. Dose-corrected AUC was comparable between single and multiple doses for both adinazolam and NDMAD; no differences were observed in 24-hr AUC at steady-state between CT and SR tablets. Fluctuation ratios were reduced for both adinazolam and NDMAD following SR tablets. Psychomotor and sedative effects were attenuated upon multiple dosing. Thus, the reduction in peak plasma NDMAD following SR tablet administration results in a lesser sedation and psychomotor impairment on acute administration, and tolerance to these effects occurs on mulitiple dosing.     

Release and Absorption Characteristics of Novel Theophylline Sustained-Release Formulations: In Vitro-in Vivo Correlation

Five new experimental sustained-release (SR) formulations of theophylline, T-l, T-l-A, T-2, T-2-A, and T-2-E, in a matrix tablet form with a protein were developed. The in vitro release of theophylline from these novel experimental formulations and two commercial (Theotrim and Theo-Dur) SR formulations, was studied for 2 hr immersed in simulated gastric fluid TS, followed by an additional 10 hr immersed in simulated intestinal fluid TS. Like Theotrim and Theo-Dur, theophylline release profiles from all the novel experimental formulations were smooth, controlled, and unaffected by changes in the pH and the proteolytic enzyme content of the incubation media. Pharmacokinetic evaluation of T-l, T-l-A, T-2-A, Theotrim, and Theo-Dur was carried out in five dogs and six healthy human volunteers under fasting conditions, using immediate-release aminophylline tablets as controls. Pharmacokinetic analysis by the Wagner–Nelson procedure revealed sustained-release absorption characteristics for all the formulations with the exception of the immediate release aminophylline tablet. For each of the formulations tested, the regression analysis results of the percentage of theophylline absorbed in dogs or humans against the mean percentage released in vitro, at the corresponding times, indicated a high correlation. These data imply that the in vivo release profiles under fasting conditions in the gastrointestinal tract of dogs and humans may be similar to those in the in vitro studies.     

Gastroretentive mucoadhesive tablet of lafutidine for controlled release and enhanced bioavailability

Abstract

Lafutidine a newly developed histamine H2-receptor antagonist having biological half-life of 1.92?±?0.94?h due to its selective absorption from upper part of gastrointestinal tract the development of mucoadhesive sustained release drug delivery system is recommended in order to enhance the bioavailability. A mucoadhesive tablets was developed using the natural polymer, sodium alginate, xanthan gum and karaya gum. Mucoadhesion is a complex phenomenon which involves wetting, adsorption and interpenetration of polymer chains. The prepared tablets of various formulations were evaluated for a total mucoadhesion time, buoyancy lag time and percentage drug released. The formulation with xanthan gum showed better results. Thus, it may be useful for prolonged drug release in stomach to improve the bioavailability and reduced dosing frequency. Non-fickians release transport was confirmed as the drug release mechanism from the optimized formulation by Korsmeyer–Peppas. The optimized formulation (B3) showed a mucoadhesive strength >35?g. In vivo study was performed using rabbits by X-ray imaging technique. Radiological evidences suggest that, a formulated tablet was well adhered for >10?h in rabbit’s stomach. Optimized lafutidine mucoadhesive tablets showed no significant change in physical appearance, drug content, mucoadhesive properties and in vitro dissolution pattern after storage at 40?°C temperature 75?±?5% relative humidity for 3 months.     

利格列汀双层缓释片的制备及体外释放研究

目的 制备一种新型利格列汀双层缓释片，并考察其体外释放行为。方法 以羟丙基甲基纤维素（hydroxyl propyl methyl cellulose，HPMC）为骨架材料、黄原胶为黏合剂，采用单因素设计筛选处方，进行利格列汀双层缓释片的制备，并绘制处方在pH 6.80介质中的体外溶出曲线；采用常规Ritger-Peppas、Higuchi、一级、零级释放曲线方程进行拟合，分析样品释药原理。结果 经优化后的样品由含药缓释层和含药速释层构成。缓释层由主成分利格列汀3 mg、缓释骨架材料HPMC（型号：K4M及K100M，用量均50 mg）、填充剂微晶纤维素100 mg、凝胶缓释基质黄原胶15 mg、润滑剂硬脂酸镁1 mg组成；速释层由主成分利格列汀2 mg、填充剂微晶纤维素10 mg、崩解剂交联聚乙烯吡咯烷酮15 mg、润滑剂硬脂酸镁1 mg组成。最终结果与零级释放方程匹配度最高，极具相关性，拟合结果r²无限接近于1。结论 成功制得利格列汀双层缓释片，并实现零级释放。     

Natural gum as mucoadhesive controlled release carriers: evaluation of Cefpodoxime Proxetil by D-Optimal design technique

Abstract

The present study deals with the development of mucoadhesive controlled release tablets of Cefpodoxime Proxetil to increase the gastric residence time and thus prolong drug release, reduce dosing frequency and improve oral bioavailability. Tablets were prepared using sodium alginate and karaya gum, a natural polymer, with a synthetic polymer hydroxypropylmethylcellulose (K100LV) and Karaya gum with HPMC K100LV in various ratios to optimize the drug release profile using D-Optimal technique. Pre- and post-compression parameters of tablets prepared with various formulations (S1–S9, C1–C9) were evaluated. The FTIR and DSC studies revealed that no physiochemical interaction between excipients and drug. The formulation S7 showed prolonged drug release, and the mechanism of drug release from the optimized formulation was confirmed using the Korsmeyer–Peppas model to be non-Fickian release transport and n value was found 0.605 indicating both diffusion and erosion mechanism from these natural gums. The optimized formulation showed mucoadhesive strength >35?g. An in vivo study was performed on rabbits using an X-ray imaging technique. The radiological evidence suggests that the tablets adheres (more than 10 hours) to a rabbit’s stomach. No significant changes were found in the physical appearance, drug content, mucoadhesive study and in vitro dissolution pattern after storage at 40?°C/75% relative humidity for 3 months.     

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。     

盐酸氨溴索缓释片体内外相关性研究

目的考察盐酸氨溴索缓释片体外释放度与体内吸收的相关性。方法应用释放度测定法研究盐酸氨溴索缓释片体外释药行为 ,采用HPLC法测定盐酸氨溴索缓释制剂在家犬体内的血药浓度 ,按照Wagner Nelson公式计算药物的吸收分数。 结果 3种自制盐酸氨溴索缓释片与参比制剂生物等效 ,以药物累积吸收百分数 f(t)与相应时刻的体外累积释放百分数F(t)建立的一元线性回归方程 ,参比制剂与 3种自制制剂的体内外相关系数分别为 0 969、0 979、0 970和 0 983。结论盐酸氨溴索缓释片的体外释放度与体内吸收具有显著的相关性。     

马来酸曲美布汀缓释片体外释药影响因素的考察

目的研究马来酸曲美布汀缓释片的体外释药影响因素。方法以紫外分光光度法为分析方法,研究马来酸曲美布汀缓释片体外释放度。结果马来酸曲美布汀缓释片的体外释药符合Higuchi和Ritger Peppas释放规律,释药速率受HPMC的规格及用量、乳糖用量、制片工艺、片剂硬度等各种因素的影响。结论体外释药规律符合缓释制剂要求,可进一步进行体内释药行为考察。     

盐酸西曲酸酯胃漂浮片的研制

目的：根据流体动力学平衡控释系统（HBS）原理研制盐酸西曲酸酯胃漂浮片，并评价其体外释药特性。方法：用正交试验设计对片剂的处方进行筛选与优化，制备盐酸西曲酸酯胃漂浮片，测定其体外释药特性。结果：以优选的处方所制备的片剂，体外释药性能良好，符合一级动力学方程和Higuchi方程，持续释药达6h以上。结论：该片剂具有明显的漂浮和缓释作用，制备工艺简便易行。