Characterization of 5-fluorouracil release from hydroxypropylmethylcellulose compression-coated tablets

Hydrogel compression-coated tablets are able to release the core drug after a period of lag time and have potential for colon-specific drug delivery based on gastrointestinal transit time concept. This study investigated the factors influencing in vitro release characteristics of a model drug 5-fluorouracil from hydroxypropylmethycellulose (HPMC) compression-coated tablets. The core tablet, prepared by a wet granulation compression method, was designed to disintegrate and dissolute quickly. To prepare the compression-coated tablets, 50% of the HPMC/lactose coat powder was precompressed first, followed by centering the core tablet and compressing with the other 50% of the coat powder. Release characteristics were evaluated in distilled water by using a Chinese Pharmacopoeia rotatable basket method. Effect of HPMC viscosity, lactose content in outer shell, and overall coating weight of outer shell on release lag time (T(lag)), and zero-order release rate (k) were studied. Release of drug from compression-coated tablets began after a time delay as a result of hydrogel swelling/retarding effect, followed by zero-order release for most of the formulations studied. HPMC of higher viscosity (K4M and K15M) provided better protection of the drug-containing core, showing increased release lag time and slower release rate. Incorporating lactose in outer shell led to decrease of T(lag) and increase of k. T(lag) and k are exponentially and linearly correlated to lactose content, expressed as weight percentage of the outer shell. Larger coating weight (W) of outer shell produced larger coating thickness (D) around core tablet, which resulted in increase in T(lag) and decrease in k. There was good fitting of a linear model for each of the four variables W, D, T(lag), and k. Hardness of the compression-coated tablets and pHs of the release media had little effect on drug release profile. It is concluded that the release lag time and release rate are able to be tailored through adjusting the formulation variables to achieve colon-specific drug delivery of 5-fluorouracil.     

Effect of HPMC and Carbopol on the release and floating properties of Gastric Floating Drug Delivery System using factorial design

The purpose of this study is to investigate the effect of formulation variables on drug release and floating properties of the delivery system. Hydroxypropyl methylcellulose (HPMC) of different viscosity grades and Carbopol 934P (CP934) were used in formulating the Gastric Floating Drug Delivery System (GFDDS) employing 2 x 3 full factorial design. Main effects and interaction terms of the formulation variables could be evaluated quantitatively by a mathematical model. It was found that both HPMC viscosity, the presence of Carbopol and their interaction had significant impact on the release and floating properties of the delivery system. The decrease in the release rate was observed with an increase in the viscosity of the polymeric system. Polymer with lower viscosity (HPMC K100LV) was shown to be beneficial than higher viscosity polymer (K4M) in improving the floating properties of GFDDS. Incorporation of Carbopol, however, was found to compromise the floating capacity of GFDDS and release rate of calcium. The observed difference in the drug release and the floating properties of GFDDS could be attributed to the difference in the basic properties of three polymers (HPMC K4M, K100LV and CP934) due to their water uptake potential and functional group substitution.     

羟丙基甲基纤维素对水溶性药物释放的影响

以维生素Ｃ为水溶性药物的模型物，三种不同粘度的羟丙基甲基纤维素制成的凝胶骨架片，以Ｋ１００Ｍ规格对维生素Ｃ的释放有延缓作用。维生素Ｃ民羟丙基甲基纤维素的四种不同比例量制成的凝胶骨架片，其中以１：１的比例量，对维生素Ｃ的释放更缓慢。在凝胶骨架片中含有乳糖时，可加快维生素Ｃ的释放。     

Oral controlled release formulations of rifampicin. Part II: Effect of formulation variables and process parameters on in vitro release

Hydrophilic controlled release matrix tablets of rifampicin, a poorly soluble drug, have been formulated using hydroxypropyl methylcellulose (HPMC) polymer (low, medium, and high viscosity) by direct compression method. Influence of formulation variables and process parameters such as drug:HPMC ratio, viscosity grade of HPMC, drug particle size, and compression force on the formulation characters and drug release has been studied. Our results indicated that the release rate of the drug and the mechanism of release from the HPMC matrices are mainly controlled by the drug:HPMC ratio and viscosity grade of the HPMC. In general, decrease in the drug particle size decreased the drug release. Lower viscosity HPMC polymer was found to be more sensitive to the effect of compression force than the higher viscosity. The formulations were found to be stable and reproducible.     

Application of mixture experimental design in the formulation and optimization of matrix tablets containing carbomer and hydroxy-propylmethylcellulose

Using mixture experimental design, the effect of carbomer (Carbopol® 971P NF) and hydroxypropylmethylcellulose (Methocel® K100M or Methocel® K4M) combination on the release profile and on the mechanism of drug liberation from matrix tablet was investigated. The numerical optimization procedure was also applied to establish and obtain formulation with desired drug release. The amount of TP released, release rate and mechanism varied with carbomer ratio in total matrix and HPMC viscosity. Increasing carbomer fractions led to a decrease in drug release. Anomalous diffusion was found in all matrices containing carbomer, while Case — II transport was predominant for tablet based on HPMC only. The predicted and obtained profiles for optimized formulations showed similarity. Those results indicate that Simplex Lattice Mixture experimental design and numerical optimization procedure can be applied during development to obtain sustained release matrix formulation with desired release profile.     

Box-Behnken效应面法优化盐酸左氧氟沙星胃漂浮缓释片处方

目的：探讨Box-behnken效应面法在优化盐酸左氧氟沙星胃漂浮缓释片处方过程中的应用。方法：以盐酸左氧氟沙星为模型药物,采用湿法制粒压片法制备左氧氟沙星胃漂浮缓释片剂。利用Box-behnken实验设计,考察三种缓释材料HPMCK 4M、卡泊姆CP934P及海藻酸钠(SA)对不同时间点释药性能和对漂浮片漂浮性能的影响,通过二项式方程拟合建立因素与响应值之间的数学关系以优化处方,对体外释药数据进行方程拟合,探讨其释药机理。结果：通过优化后的最佳处方为HPMC K4M 30 %、卡泊姆CP934P 12.3 %、海藻酸钠(SA) 28.6%,优化处方的实测值与预测值之间的偏差较小;药物的释药机制为骨架溶蚀与药物扩散双重作用。结论：Box-behnken效应面法优化法建立的模型可以用于盐酸左氧氟沙星缓释片处方的优化。     

Characterization of 5-Fluorouracil Release from Hydroxypropylmethylcellulose Compression-Coated Tablets

Hydrogel compression-coated tablets are able to release the core drug after a period of lag time and have potential for colon-specific drug delivery based on gastrointestinal transit time concept. This study investigated the factors influencing in vitro release characteristics of a model drug 5-fluorouracil from hydroxypropylmethycellulose (HPMC) compression-coated tablets. The core tablet, prepared by a wet granulation compression method, was designed to disintegrate and dissolute quickly. To prepare the compression-coated tablets, 50% of the HPMC/lactose coat powder was precompressed first, followed by centering the core tablet and compressing with the other 50% of the coat powder. Release characteristics were evaluated in distilled water by using a Chinese Pharmacopoeia rotatable basket method. Effect of HPMC viscosity, lactose content in outer shell, and overall coating weight of outer shell on release lag time (T_lag), and zero-order release rate (k) were studied. Release of drug from compression-coated tablets began after a time delay as a result of hydrogel swelling/retarding effect, followed by zero-order release for most of the formulations studied. HPMC of higher viscosity (K4M and K15M) provided better protection of the drug-containing core, showing increased release lag time and slower release rate. Incorporating lactose in outer shell led to decrease of T_lag and increase of k. T_lag and k are exponentially and linearly correlated to lactose content, expressed as weight percentage of the outer shell. Larger coating weight (W) of outer shell produced larger coating thickness (D) around core tablet, which resulted in increase in T_lag and decrease in k. There was good fitting of a linear model for each of the four variables W, D, T_lag, and k. Hardness of the compression-coated tablets and pHs of the release media had little effect on drug release profile. It is concluded that the release lag time and release rate are able to be tailored through adjusting the formulation variables to achieve colon-specific drug delivery of 5-fluorouracil.     

Benzydamine hydrochloride buccal bioadhesive gels designed for oral ulcers: Preparation,rheological, textural,mucoadhesive and release properties

This study developed and examined the characterization of Benzidamine hydrochloride (BNZ) bioadhesive gels as platforms for oral ulcer treatments. Bioadhesive gels were prepared with four different hydroxypropylmethylcellulose (HPMC) types (E5, E15, E50 and K100M) with different ratios. Each formulation was characterized in terms of drug release, rheological, mechanical properties and adhesion to a buccal bovine mucosa. Drug release was significantly decreased as the concentration and individual viscosity of each polymeric component increased due to improved viscosity of the gel formulations. The amount of drug released for the formulations ranged from 0.76?±?0.07 and 1.14?±?0.01 (mg/cm²?±?SD). Formulations exhibited pseudoplastic flow and all formulations, increasing the concentration of HPMC content significantly raised storage modulus (G′), loss modulus (G″), dynamic viscosity (?′) at 37°C. Increasing concentration of each polymeric component also significantly improved the hardness, compressibility, adhesiveness, cohesiveness and mucoadhesion but decreased the elasticity of the gel formulations. All formulations showed non-Fickian diffusion due to the relaxation and swelling of the polymers with water. In conclusion, the formulations studied showed a wide range of mechanical and drug diffusion characteristics. On the basis of the obtained data, the bioadhesive gel formulation which was prepared with 2.5% HPMC K 100M was determined as the most appropriate formulation for buccal application in means of possessing suitable mechanical properties, exhibiting high cohesion and bioadhesion.     

人工神经网络预测HPMC缓释片中易溶性药物的释放

目的应用BP人工神经网络模型预测水溶性药物从HPMC缓释片中的释放。方法以6种不同溶解性的水溶性药物(对乙酰氨基酚、氧氟沙星、盐酸环丙沙星、乳酸左氧氟沙星、多索茶碱、氯苯那敏、维拉帕米)为模型药物,设计62个处方,其中前面55个处方作为训练处方,另外7个处方作为验证处方,压制HPMC缓释片,进行释放度检查。以溶解度、载药量、HPMC的量、HPMC的固有黏度、MCC的量、PVP的浓度和药物溶出仪的转速作为自变量,药物在各个取样时间点的累积释放量作为输出,建立BP人工神经网络模型,并与响应面法进行对照,通过线性回归法和相似因子法比较人工神经网络和响应面法的预测能力,借助三维图说明各个变量对药物释放的影响。结果线性回归和相似因子法表明人工神经网络较响应面法的预测值与实际测定值更吻合,更能充分地说明单因素对药物释放的影响规律。结论人工神经网络可以代替响应面法处理HPMC缓释片处方设计中的不同溶解度的水溶性药物的多因素多响应的非线性问题而且可以推广到别的制剂设计中。     

效应面法优化尼美舒利双层缓释片处方

采用正交设计及星点设计-效应面法对尼美舒利双层缓释片处方进行优化。优化后的处方如下：（Ⅰ）速释层：尼美舒利,50 mg;乳糖,92 mg;淀粉,22 mg;CCMC-Na,14 mg;PVP K30,1 mg;微粉硅胶,1 mg;硬脂酸镁,0.9 mg;氧化铁红,0.1 mg;（Ⅱ）缓释层：尼美舒利,150 mg;HPMC K100LV,26 mg;HPMC K4M,33 mg;乳糖,54 mg;PVP K30,1 mg;微粉硅胶,1 mg;硬脂酸镁,0.9 mg。优化后的处方在初期药物快速释放（10 min释放15%）,后期缓慢释放持续一段时间（16 h）,具有双相释放特征,且放置6个月后无明显变化。     

响应面法优化富马酸喹硫平缓释片处方

目的:优化富马酸喹硫平缓释片处方。方法:以累积释放度综合评分作为响应值,采用3因素3水平的响应面法,确定富马酸喹硫平缓释片处方中羟丙甲纤维素(HPMC)的黏度、用量与枸橼酸钠、乳糖的用量,并探讨其体外释药机制。结果:骨架材料选择HPMC K15M,考虑到实际操作便利确定其用量为13.5%,枸橼酸钠用量为9.5%,乳糖用量为14%。缓释片体外释放符合Higuchi方程,释药机制为扩散和溶蚀并存的双重机制。结论:筛选所得的富马酸喹硫平缓释片处方工艺稳定可行,有一定的缓释作用。     

A framework to investigate drug release variability arising from hypromellose viscosity specifications in controlled release matrix tablets

Substitution level, particle size, and molecular weight are key properties of hypromellose (HPMC) known to be important to its performance in pharmaceutical-controlled release applications. The hypromellose monographs indirectly specify acceptable ranges for the molecular weight of HPMC products, expressed as the apparent viscosity of a 2% aqueous solution. The purpose of this study was to provide a framework to systematically investigate the amount of drug release variability that might be expected for typical controlled release formulations over the monograph viscosity ranges for hypromellose. An approach to estimate the expected drug release variability was developed based on scaling laws in the literature. New experimental data were generated with pentoxifylline, theophylline, and hydrochlorothiazide as model drugs to explore the applicability of this approach to a range of formulations. This methodology predicted that drug release variability over the United States Pharmacopeia (USP) viscosity ranges would be greatest for the lower viscosity grades of hypromellose, such as E50 and K100 LV. Drug release variability due to hypromellose viscosity variations is expected to be larger for formulations having substantial contributions from erosional drug release, and smaller for formulations with a predominantly diffusional drug release mechanism. These predictions need to be validated experimentally.     

格列喹酮缓释片的处方设计

目的：对格列喹酮缓释片进行处方研究。方法：以药物的累积释放度为标准,同时结合相似因子,首先进行单因素试验,确定影响药物释放的主要因素,在此基础上,以HPMC（K4M）及乳糖的含量为变量,进行比较试验,采用综合评分法确定最优处方。并且对最优处方进行验证。结果：最优处方为格列喹酮、HPMC（K4M）、乳糖用量分别为60mg、30mg、55mg,70％乙醇为粘合剂,所制得的格列喹酮缓释片在2,6,12h的体外累积释放度分别为（19．82±0．92）％,（51．07±0．95）％和（83．48±0．71）％。结论：格列喹酮缓释片体外显示出缓释行为,释放度符合规定,可进一步研究开发。     

Formulation and optimization of sustained release matrix tablet of metformin HCl 500 mg using response surface methodology

The aim of the current study was to design an oral sustained release matrix tablet of metformin HCl and to optimize the drug release profile using response surface methodology. Tablets were prepared by non-aqueous wet granulation method using HPMC K 15M as matrix forming polymer. A central composite design for 2 factors at 3 levels each was employed to systematically optimize drug release profile. HPMC K 15M (X(1)) and PVP K 30 (X(2)) were taken as the independent variables. The dependent variables selected were % of drug released in 1 hr (rel(1 hr)), % of drug released in 8 hrs (rel(8 hrs)) and time to 50% drug release (t(50%)). Contour plots were drawn, and optimum formulations were selected by feasibility and grid searches. The formulated tablets followed Higuchi drug release kinetics and diffusion was the dominant mechanism of drug release, resulting in regulated and complete release within 8 hrs. The polymer (HPMC K 15M) and binder (PVP K 30) had significant effect on the drug release from the tablets (p<0.05). Polynomial mathematical models, generated for various response variables using multiple linear regression analysis, were found to be statistically significant (p<0.05). Validation of optimization study, performed using 8 confirmatory runs, indicated very high degree of prognostic ability of response surface methodology, with mean percentage error (+/-S.D.) 0.0437+/-0.3285. Besides unraveling the effect of the 2 factors on the in vitro drug release, the study helped in finding the optimum formulation with sustained drug release.     

Once-daily propranolol extended-release tablet dosage form: formulation design and in vitro/in vivo investigation.

The purpose of this study was to develop and optimize the propranolol once-daily extended release formulations containing HPMC, Microcrystalline cellulose (MCC) and lactose. In vitro studies, the response surface methodology and multiple response optimization utilizing the polynomial equation were used to search for the optimal formulation with specific release rate at different time intervals. The constrained mixture experimental design was used to prepare systematic model formulations, which were composed of three formulation variables: the content of HPMC (X(1)) MCC (X(2)) and lactose (X(3)). The drug release percent at 1.5, 4, 8, 14 and 24 h were the target responses and were restricted to 15-30, 35-55, 55-75, 75-90 and 90-110%, respectively. The results showed that the optimized formulation provided a dissolution pattern equivalent to the predicted curve, which indicated that the optimal formulation could be obtained using response surface methodology. The mechanism of drug release from HMPC matrix tablets followed non-Fickian diffusion. In the vivo study, the MRT was prolonged for matrix tablets when compared with commercial immediate release tablets. Furthermore, a linear relationship between in vitro dissolution and in vivo absorption was observed in the beagle dogs.     

optimization of extended zero-order release gliclazide tablets using D-optimal mixture design

The objective of this study was to develop and optimize the gliclazide extended-release formulations by using simultaneously combination of two hydrophilic polymers: HPMC K 15M and sodium alginate as retardant. D-Optimal mixture design was employed to evaluate the effect of HPMC (X(1)), lactose (X(2)), and sodium alginate (X(3)) concentrations on the release rate of gliclazide from the matrices. The drug release percent at 3, 6, 9 and 12 h were the target responses and were restricted to 20-30, 45-55, 70-80 and 90-100%, respectively. Response surface methodology and multiple response optimization utilizing the polynomial equation were used to search for the optimal formulation with specific release rate at different time intervals. Validation of the optimization study indicated high degree of prognostic ability of response surface methodology. The mechanism of drug release from optimized extended-release matrix tablets was followed by the zero-order release pattern. This study demonstrated that D-optimal mixture experimental design facilitated the formulation and optimization of extended release hydrophilic matrix systems of gliclazide.     

人工神经网络预测别嘌醇HP MC缓释片药物释放

目的用人工神经网络模型定量的预测HPMC的量和其固有黏度对药物释放的影响。方法以难溶性药物别嘌醇为模型药物,固定其他因素,HPMC的量和HPMC的固有黏度作为自变量,设计了18个处方并进行释放度检查;其中的13个处方作为训练处方,其他5个处方为验证处方,将上述的变量作为人工神经的输入,以药物在各个取样时间点的释放为输出,采用剔除一点交叉验证法建立人工神经网络模型。通过线性回归和相似因子说明人工神经网络的预测能力。结果训练和验证处方人工神经网络预测值与实际测定相符。结论建立BP人工神经网络,根据HPMC的量和其固有黏度可以定量的预测药物在各个时间点的药物释放。     

Optimization of pH-independent release of nicardipine hydrochloride extended-release matrix tablets using response surface methodology

The purpose of this study was to optimize the pH-dependent release of nicardipine hydrochloride extended release formulations by using simultaneously combination two hydrophilic polymers: hydroxypropylmethylcellulose (HPMC) and sodium alginate as retardant and avicel as additive. The constrained mixture experimental design was used to prepare systematic model formulations which were composed of three formulation variables: the content of HPMC (X1), avicel (X2), and sodium alginate (X3). The response surface methodology (RSM) and multiple response optimization utilizing the polynomial equation were used to search for the optimal formulation with specific release rate at different time intervals and to quantify the effect of each formulation variables. The drug release percent at 3, 6 and 12 h were the target responses and were restricted to 10-30% (Y3h), 40-65% (Y6h) and not less than 80% (Y12h), respectively. The results showed that the effect of combination of HPMC and sodium alginate was the most influence factor on the drug release from extended-release matrix tablets. The observed results of Y3h, Y6h and Y12h coincided well with the predictions in the RSM optimization technique, indicating it was quite useful for optimizing pharmaceutical formulation. The mechanism of drug release from extended-release matrix tablets was dependent on the added amount of alginate. The release kinetic of drug from HPMC matrix tablets with alginate was followed the zero-order release pattern.     

Influence of cellulose ether polymers on ketoprofen release from hydrophilic matrix tablets.

The present work reports the study of different ketoprofen:excipient formulations, in order to determine the effect of the polymer substitution and type of diluent on the drug-release mechanism. Substituted cellulose-methylcellulose, hydroxypropylcellulose and hydroxypropylmethylcellulose were used as polymers, while lactose monohydrate and beta-cyclodextrin were tested as diluents. Distinct test formulations were prepared, containing 57.14% of ketoprofen, 20.00% of polymer, 20.29% of diluent, and 1.71% of talc/0.86% of magnesium stearate as lubricants. The tablets were tested for their drug content, weight variation, hardness, thickness, tensile strength, friability, swelling and release ratio. Polymers MC25 and HPC were found not to be appropriate for the preparation of modified release ketoprofen hydrophilic matrix tablets, while HPMC K15M and K100M showed to be advantageous. The analysis of the release profiles in the light of distinct kinetic models (zero-order, first-order, Higuchi and Korsmeyer-Peppas) led to the conclusion that the type of polymer did not influence the release mechanism of the drug. The mean dissolution time (MDT) was determined, the highest MDT value being obtained for HPMC formulations. Moreover, the drug-release process was found to be slightly influenced by the type of diluent, either lactose or beta-cyclodextrin.     

Floating matrix dosage form for propranolol hydrochloride based on gas formation technique: development and in vitro evaluation

Gastroretentive tablets of propranolol hydrochloride were developed by direct compression method using citric acid and sodium bicarbonate as the effervescent base. Hydroxypropyl methylcellulose; HPMC K15M was used to prepare the floating tablets to retard the drug release for 12h in stomach. Na-carboxymethyl cellulose (NaCMC) or carbopol 934P was added to alter the drug release profile or the dimensional stability of the formulation. Dicalcium phosphate (DCP) was used as filler. Formulations were evaluated for floating lag time, duration of floating, dimensional stability, drug content and in vitro drug release profile. The formulations were found to have floating lag time less than 1min. It was found that the dimensional stability of the formulations increase with increasing concentration of the swelling agent. The release mechanism of propranolol hydrochloride from floating tablets was evaluated on the basis of Peppas and Higuchi model. The ana value of the formulations ranged from 0.5201 to 0.7367 (0.5相似文献