Modulation of drug release kinetics of shellac-based matrix tablets by in-situ polymerization through annealing process.

A new oral-controlled release matrix tablet based on shellac polymer was designed and developed, using metronidazole (MZ) as a model drug. The shellac-based matrix tablets were prepared by wet granulation using different amounts of shellac and lactose. The effect of annealing temperature and pH of medium on drug release from matrix tablets was investigated. The increased amount of shellac and increased annealing temperature significantly affected the physical properties (i.e., tablet hardness and tablet disintegration) and MZ release from the matrix tablets. The in-situ polymerization played a major role on the changes in shellac properties during annealing process. Though the shellac did not dissolve in acid medium, the MZ release in 0.1N HCl was faster than in pH 7.3 buffer, resulting from a higher solubility of MZ in acid medium. The modulation of MZ release kinetics from shellac-based matrix tablets could be accomplished by varying the amount of shellac or annealing temperature. The release kinetics was shifted from relaxation-controlled release to diffusion-controlled release when the amount of shellac or the annealing temperature was increased.     

Carboxymethyl high amylose starch for F4 fimbriae gastro-resistant oral formulation

Texture analysis is a new approach in pharmaceutical research and development; this study evaluated the correlation between drug dissolution and polymer hydration from a modified release matrix tablet of pseudoephedrine hydrochloride using a texture analyzer. A series of matrix tablets of pseudoephedrine was designed and prepared. Modified drug release was achieved by combined use of matrix excipients Polyox WSR301 (PEO) and Compritol 888ATO (GB). Dissolution profiles of the tablets were assessed using USP Method II. Polymer swelling behaviors during dissolution were measured using a texture analyzer. Increase in proportion of PEO and GB in the formulation reduced drug dissolution within the first 90 min. However, drug release was complete in 6h due to high aqueous solubility of pseudoephedrine. Linear correlations were observed among drug dissolution, polymer content and parameters of texture analysis including hydrogel thickness and AUC(TA) for formulations that contained hydrophilic PEO. The study demonstrated a unique application of a texture analyzer in characterization of modified release matrix tablets.     

卡波姆71G和羟丙基甲基纤维素在氢氯噻嗪骨架缓释片中的应用

目的:以氢氯噻嗪为模型药物,卡波姆71G和羟丙基甲基纤维素(HPMCSH4000)为骨架材料制备氢氯噻嗪缓释片,并对影响其释放的因素进行考察.方法:以HPMCSH4000和卡波姆71G为亲水性骨架材料,湿颗粒法压片制备氢氯噻嗪缓释片,采用中华人民共和国药典2000年版二部收载的溶出度测定方法II(桨法),测定药物的体外释放度,以一级方程的相关系数(r),t30,t50和t75为指标进行处方筛选,并考察影响氢氯噻嗪释放的因素.结果:最优处方的r,t30,t50和t75符合实验要求,制备的缓释片释放曲线符合一级释放方程,卡波姆71G和HPMCSH4000的用量、压片压力、释放介质的pH值、桨法转速对药物的体外释放均有一定影响.结论:以卡波姆71G和HPMCSH4000为骨架材料,可以制备出具有理想释药的氢氯噻嗪骨架缓释片.     

用渗滤理论研究乙基纤维素骨架片的最适压片力范围

目的　用渗滤理论研究制备阿司匹林-乙基纤维素骨架片的最适压片力范围。方法　使用不同的压片力(3～30 kN)制备了含阿司匹林40%的阿司匹林-乙基纤维素骨架片,测定了溶出曲线,用Higuchi方程和Ritger-Peppas方程对溶出数据进行拟合。将拟合的Higuchi方程的斜率b值和计算得到的片剂的孔隙率ε,代入渗滤理论推导出的公式中,可计算出表观扩散系数D和片剂溶出性能参数β,分别以D对ε及β对ε回归,可得到临界孔隙率ε_c,由β-ε,D-ε和β-ε₀曲线可推知最适压片力范围。结果　压片力在9～18 kN时,药物释放遵从Higuchi模型方程,片剂以骨架扩散机制释药,且释药速度适中,因此9～18 kN为最适压片力范围。低于9 kN时,片子的初始孔隙率太大,药物溶出过快;高于18 kN时,药物溶出过慢,呈异常扩散机制释放药物。结论　渗滤理论可较清楚地阐明阿司匹林骨架片的释药机制,并可得到制备阿司匹林片的最适压片力范围。     

The physicodynamic properties of mucoadhesive polymeric films developed as female controlled drug delivery system

Phenoporlamine hydrochloride is a novel compound that is used for the treatment of hypertension. The purpose of this study was to develop a sustained release tablet for phenoporlamine hydrochloride because of its short biological half-life. Three floating matrix formulations of phenoporlamine hydrochloride based on gas forming agent were prepared. Hydroxypropyl methylcellulose K4M and Carbopol 971P NF were used in formulating the hydrogel drug delivery system. Incorporation sodium bicarbonate into matrix resulted in the tablet floating over simulated gastric fluid for more than 6 h. The dissolution profiles of all tablets showed non-Fickian diffusion in simulated gastric fluid. Moreover, release of the drug from these tablets was pH-dependent. In vivo evaluations of these formulations of phenoporlamine hydrochloride were conducted in six healthy male human volunteers to compare the sustained release tablets with immediate release tablets. Data obtained in these studies demonstrated that the floating matrix tablet containing more Carbopol was capable of sustained delivery of the drug for longer periods with increased bioavailability and the relative bioavailability of formulation (containing 25% Carbopol 971P NF, 8.3% HPMC K4M) showed the best bioequivalency to the reference tablet (the relative bioavailability was 1.11 ± 0.19).     

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。     

Modification of physicochemical and mechanical properties of shellac by partial hydrolysis

The shellac was modified by partial hydrolysis with 2.0% (w/w) NaOH for different times. The hydrolysed shellac was then evaluated for physicochemical and film properties in comparison with native shellac. The tablets coated with native and hydrolysed shellac were also evaluated. The results demonstrated that acid value (AV) of shellac increased with prolongation of hydrolysis time. The solubility of shellac in buffer solution (pH < or = 7) gradually increased with increasing hydrolysis time. The films prepared from hydrolysed shellac were more flexible and soft than those prepared from native shellac. The increasing of flexibility was correlated with the increasing of soft resin in shellac. The water vapor permeability of hydrolysed shellac film was lower than that of native shellac film. The higher acid permeability of the tablet coated with hydrolysed shellac was observed. In ethanol-based film coating, shellac had lower solubility and thus lower drug dissolution from coated tablets was observed. In ammonia-based film coating, the solubility of shellac was improved higher nearby pH 7.0 by an ammonium neutralisation method because of forming well-soluble salts, thereby higher drug dissolution was obtained. Partial hydrolysis provided modified shellac, which is more effective for ammonium salt formation, thus very higher drug dissolution was achieved in the ammonia-based coated tablets.     

Effect of Processing Methods and Heat Treatment on the Formation of Wax Matrix Tablets for Sustained Drug Release

The objective of this study was to evaluate the effects of processing methods and heat treatment on matrix formation and subsequent drug release from wax matrix tablets for controlled release. Phenylpropanolamine hydrochloride (PPA) and Compritol® were processed with appropriate diluent(s) using either dry blending (DB), wet granulation (WG), partial melt granulation (PMG), or melt granulation (MG). Then the tablets were heat-treated at 80°C. Particle size distribution and compressibility, along with drug release, tablet micro-morphology, wettability, porosity, and tortuosity were investigated. The drug release was different for the four processing methods even though the tablet formulation was identical. Heat treatment further retarded drug release and its effect was related to the previous manufacturing processes. Scanning Electron Microscopy (SEM) showed that heat treatment redistributed the wax and formed a film-like structure covering drug and excipients. The contact angle of tablets made from DB, WG, and PMG methods increased after heat treatment, while that of tablets made from DB, WG, and PMG methods increased after heat treatment, while that of tablets made from MG remained constant. Tablet tortuosity calculated from drug release rate constants increased dramatically after heat treatment. Drug release from the wax tablets with or without heat treatment was best described by the Higuchi equation. Different processing methods produced different matrix structures that resulted in different drug release rates. Heat treatment retarded drug release mainly by increasing tortuosity of the matrix. Contact angle measurement and SEM analysis indicated that heat treatment caused the wax to melt, redistribute, coat the drug and diluents, and form a network structure.     

无时滞非达霉素肠溶片的制备及溶出评价

目的: 制备无时滞非达霉素肠溶片,考察其溶出特性。方法: 采用湿法制粒工艺,通过正交实验进行片芯优化,以甲基丙烯酸与丙烯酸乙酯共聚物为肠溶包衣材料,制备非达霉素肠溶片,以体外释放度为指标,考察其溶出行为。结果: 片芯中羟丙甲纤维素和交联羧甲基纤维素钠的用量分别为1.2%和4.5%,微晶纤维素和淀粉的比例为3:1,肠溶层共聚物的比例为50%时,制备的非达霉素肠溶片在pH1.0盐酸中2h释放度小于10%,在pH4.5醋酸盐缓冲液中可以崩解释放,在pH6.8磷酸盐缓冲液中快速释放,10min释放度大于60%。结论: 制备的非达霉素肠溶片与普通肠溶片相比无时滞效应,有望进行工业化生产。     

Effect of processing methods and heat treatment on the formation of wax matrix tablets for sustained drug release.

The objective of this study was to evaluate the effects of processing methods and heat treatment on matrix formation and subsequent drug release from wax matrix tablets for controlled release. Phenylpropanolamine hydrochloride (PPA) and Compritol were processed with appropriate diluent(s) using either dry blending (DB), wet granulation (WG), partial melt granulation (PMG), or melt granulation (MG). Then the tablets were heat-treated at 80 degrees C. Particle size distribution and compressibility, along with drug release, tablet micro-morphology, wettability, porosity, and tortuosity were investigated. The drug release was different for the four processing methods even though the tablet formulation was identical. Heat treatment further retarded drug release and its effect was related to the previous manufacturing processes. Scanning Electron Microscopy (SEM) showed that heat treatment redistributed the wax and formed a film-like structure covering drug and excipients. The contact angle of tablets made from DB, WG, and PMG methods increased after heat treatment, while that of tablets made from MG remained constant. Tablet tortuosity calculated from drug release rate constants increased dramatically after heat treatment. Drug release from the wax tablets with or without heat treatment was best described by the Higuchi equation. Different processing methods produced different matrix structures that resulted in different drug release rates. Heat treatment retarded drug release mainly by increasing tortuosity of the matrix. Contact angle measurement and SEM analysis indicated that heat treatment caused the wax to melt, redistribute, coat the drug and diluents, and form a network structure.     

熔融制粒法制备盐酸二甲双胍缓释片

目的制备盐酸二甲双胍缓释片,并考察其释药行为及影响因素。方法以山嵛酸甘油酯为骨架材料,微晶纤维素为致孔剂,采用熔融制粒技术制备盐酸二甲双胍缓释片,并考察不同释放介质,山嵛酸甘油酯、微晶纤维素的不同用量以及制备工艺参数等对该缓释片体外释放的影响。结果山嵛酸甘油酯和微晶纤维素的用量为药物释放的主要影响因素,制备的缓释片具有明显的缓释特征,体外释药过程符合零级动力学模型。结论采用山嵛酸甘油酯作为蜡质骨架材料,结合其他辅料,采用熔融制粒技术可制备日服1次的盐酸二甲双胍缓释片。     

盐酸丁螺环酮缓释片的制备及体外释放研究

目的 :为了减少给药次数和减小药物的毒副作用 ,制备盐酸丁螺环酮缓释片。方法 :采用亲水凝胶骨架材料 (HPMC)制备该缓释片 ,并考察药物与HPMC不同比例组成、HPMC不同粘度等对该水溶性药物释放的影响。结果 :药物 /HPMC之比为影响释放过程的主要因素 ,HPMC(高粘度 )的粘度与药物释放无关 ,且该骨架片的释药与释放介质的 pH无关。 结论 :该缓释片制备工艺简单 ,缓释速率可控。     

Preparation and evaluation of a novel delayed-onset sustained-release system of propranolol hydrochloride

The objective of this work was to prepare and evaluate a new delayed-onset sustained-release system, comprising a sustained-release core tablet with hydroxypropyl methylcellulose as polymer matrix and an ethylcellulose/Eudragit L coating capable of delaying the drug release. The sustained core containing propranolol hydrochloride as the model drug was prepared by granulate tableting and the polymer coating was applied in a computer-controlled coating pan. The dissolution tests demonstrated that the in-vitro drug release was pH-dependent with sufficient gastric resistance, and the lag time (t(10%)) could be controlled by adjusting the coating level. Three dosage forms including commercial tablet, sustained-release tablet and the delayed-onset sustained-release tablet were administrated to six beagle dogs and the plasma levels of propranolol hydrochloride were measured with high-performance liquid chromatography. The delayed-onset sustained-release tablet had a lag time of 3.0 h in-vitro and 3.5 h in-vivo, and a t(max) of 7.0 h. The relative bioavailability for delayed-onset sustained-release tablet was 96.98% compared with commercial tablets. The results indicate that the new propranolol delayed-onset sustained-release system could achieve a relatively constant drug release followed by a programmed lag time, and this may provide a promising drug delivery form for chronopharmacotherapy of certain cardiovascular diseases.     

盐酸溴己新缓释片的制备及体外释放度研究

目的制备盐酸溴已新（Bromhexine hydrochloride．BH）缓释片。方法以聚乙烯毗咯烷酮（PVP）为载体。将盐酸溴己新制成固体分散体．再以羟丙甲基纤维素（HPMC）为骨架材料,采用湿法制粒压片制备盐酸溴己新缓释片,并进行体外释放度试验。结果所制备的缓释片12h内呈现良好的缓释特性,符合Higuchi方程。结论盐酸澳己新缓释片体外释药缓慢、平稳,符合设计要求。     

In vitro controlled release of alfuzosin hydrochloride using HPMC-based matrix tablets and its comparison with marketed product

The present study is an attempt to formulate a controlled-release matrix tablet formulation for alfuzosin hydrochloride by using low viscous hydroxy propyl methyl cellulose (HPMC K-100 and HPMC 15cps) and its comparison with marketed product. Different batches of tablets containing 10 mg of alfuzosin were prepared by direct compression technique and evaluated for their physical properties, drug content, and in vitro drug release. All the formulations had a good physical integrity, and the drug content between the batches did not vary by more than 1%. Drug release from the matrix tablets was carried out for 12 hr and showed that the release rate was not highly significant with different ratios of HPMC K-100 and HPMC15cps. Similar dissolution profiles were observed between formulation F3 and the marketed product throughout the study period. The calculated regression coefficients showed a higher r2 value with zero-order kinetics and Higuchi model in all the cases. Although both the models could be applicable, zero-order kinetics seems to be better. Hence, it can be concluded that the use of low viscous hydrophilic polymer of different grades (HPMC K-100 and HPMC 15cps) can control the alfuzosin release for a period of 12 hr and was comparable to the marketed product.     

盐酸氨溴索缓释片的制备及释放度研究

目的 制备盐酸氨溴索缓释片,进行体外释放度研究。方法以羟丙甲基纤维素为骨架材料,70％乙醇为粘合剂。采用湿法制粒压片。以紫外-可见分光光度法洲定其在不同释效介质中的释放度。结果所研制的缓释片缓释效果良好。结论用羟丙甲基纤维素作为骨架材料能达到较好的缓释作用。     

Design and in vitro/in vivo evaluation of novel nicorandil extended release matrix tablets based on hydrophilic interpolymer complexes and a hydrophobic waxy polymer.

The purpose of this work was to develop an extended release matrix tablet of nicorandil; a freely water soluble drug used in cardiovascular diseases. Chitosan (CH)/hyaluronate sodium (HA), pectin (PE) or alginate sodium (AL) interpolymer complexes (IPCs) were prepared. The optimum IPCs (CH:HA, 40:60), (CH:PE, 30:70) and (CH:AL, 20:80) were characterized by Fourier transform infrared spectroscopy. The IPCs were based on electrostatic interactions between protonated amine groups of CH and carboxylate groups of HA, PE or AL. Nicorandil matrix tablets were prepared using the optimum IPCs, alone or in combination with Imwitor((R)) 900K. Evaluations such as weight variation, thickness, content uniformity, friability, disintegration and in vitro release studies were performed. The tablets showed acceptable pharmacotechnical properties and complied with compendial requirements. Results of the dissolution studies revealed that formula F11 (CH:AL, 20:80) IPC:Imwitor((R)) 900K, 3:1) could extend drug release >8h. Most formulae exhibited non-Fickian diffusion drug release profiles. When compared to the immediate release Ikorel((R)) tablet, the duration of effective nicorandil therapeutic concentration from formula F11, in healthy human volunteers, was significantly (P<0.05) extended from 4 to 8h with expected lowering in side effects potential.     

盐酸司他斯汀分散片的处方工艺研究

目的采用L9(34)正交设计研究盐酸司他斯汀分散片的处方工艺,优选最佳处方工艺。方法采用湿法制粒压片优选工艺条件,以微晶纤维素、聚乙烯吡咯烷酮和羧甲基淀粉钠用量为考察因素,以分散片的分散时间和10 min溶出度为考察指标,优选最佳处方组成。结果优选出的最佳处方为微晶纤维素用量40%、聚乙烯吡咯烷酮2%、羧甲基淀粉钠10%,所制备的片剂与普通片比较,溶出速度更快。结论通过研究筛选出了合适的盐酸司他斯汀分散片处方工艺。     

Dosage form design and in vitro/in vivo evaluation of cevimeline extended-release tablet formulations

The objective of the present work is to develop an extended-release dosage form of cevimeline. Two types of extended-release tablets (simple matrix tablets and press-coated tablets) were prepared and their potential as extended-release dosage forms were assessed. Simple matrix tablets have a large amount of hydroxypropylcellulose as a rate-controlling polymer and the matrix is homogeneous throughout the tablet. The press-coated tablets consisted of a matrix core tablet, which was completely surrounded by an outer shell containing a large amount of hydroxypropylcellulose. The simple matrix tablets could not sustain the release of cevimeline effectively. In contrast, the press-coated tablets showed a slower dissolution rate compared with simple matrix tablets and the release curve was nearly linear. The dissolution of cevimeline from the press-coated tablets was not markedly affected by the pH of the dissolution medium or by a paddle rotating speed over the range of 50–200 rpm. Furthermore, cevimeline was constantly released from the press-coated tablets in the gastrointestinal tract and the steady-state plasma drug levels were maintained in beagle dogs. These results suggested that the designed PC tablets have a potential for extended-release dosage forms.     

Properties of lipophilic matrix tablets containing phenylpropanolamine hydrochloride prepared by hot-melt extrusion.

The objective of the present study was to investigate the influence of formulation factors on the physical properties of hot-melt extruded granules and compressed tablets containing wax as a thermal binder/retarding agent, and to compare the properties of granules and tablets with those prepared by a high-shear melt granulation (MG) method. Powder blends containing phenylpropanolamine hydrochloride, Precirol and various excipients were extruded in a single-screw extruder at open-end discharge conditions. The extrudates were then passed through a 14-mesh screen to form granules. The extrusion conditions and the optimum amount of wax to function as the thermal binder were dependent on the properties of the filler excipients. At the same wax level, drug release from tablets decreased in the order of using microcrystalline cellulose (MCC), lactose and Emcompress as the filler excipient. The observed differences in the dissolution properties of the tablets were due to the differences in the solubility, swellability and density of the filler excipients. Replacing Precirol with Sterotex K, a higher melting point wax, resulted in slightly increased dissolution rates, when the extrusion was performed at the same temperature conditions. Hot-melt extruded granules were observed to be less spherical than high-shear melt granules and showed lower values of bulk/tap densities. However, tablets containing MCC or lactose granules prepared by hot-melt extrusion (HME) exhibited higher hardness values. Slower drug release rates were found for tablets containing MCC by HME compared with MG. Analysis of the hot-melt extruded granules showed better drug content uniformity among granules of different size ranges compared with high-shear melt granules, resulting in a more reproducible drug release from the corresponding tablets.