药物树脂复合物的表面包衣法微囊化工艺

以马来酸氯苯那敏为模型药物,采用离子交换树脂(Amberlite IRP-69)为载体制备药物树脂复合物。再以丙烯酸树脂(Eudragit RS100)为包衣材料,通过离子交换的方式对氯苯那敏树脂复合物进行表面包衣,并对表面包衣工艺参数的影响进行单因素考察,以期制备具有良好缓释性能的氯苯那敏树脂复合物微囊。在本试验范围内,药物树脂复合物的载药量越高、Eudragit RS100浓度越高、反应介质(95%乙醇)用量越多以及反应温度越高,药物释放越慢。上述结果提示,表面包衣法制备药物树脂复合物缓释微囊的生产操作简单,工艺重现性好,可进一步作制剂加工。     

桂枝、当归挥发油微囊处方优化及体内药动学研究

目的 优化桂枝、当归挥发油微囊的处方，对处方优化后制备的微囊进行相关表征和大鼠体内药动学研究。方法 采用喷雾干燥法制备桂枝、当归挥发油微囊。以载药量和包封率为指标，通过Box-Behnken设计-效应面法优化处方。采用傅里叶变换红外光谱和扫描电镜方法对处方优化后制备的微囊进行表征。按照100 mg·kg^-1的剂量灌胃给药后采血，HPLC测定血药浓度，比较体内药动学行为。结果 最佳处方为芯材-囊材比1∶1.7，囊材浓度为10.25%，复合囊材辛烯基琥珀酸淀粉钠/麦芽糊精比为3.8∶1，高压均质压力为20 MPa，喷雾干燥进口温度为185 ℃。在该条件下，测得微囊的载药量为(18.94±1.09)%，包封率(96.03±2.91)%。傅里叶变换红外光谱和扫描电镜结果表明，挥发油已成功被包覆在囊壁材料中，微囊基本形状为球形，表面凹陷但无明显裂缝。体内药动学结果显示，微囊组的达峰时间(t_max)、半衰期(t_1/2)、清除率(CL)、时间-曲线下面积(AUC_0-t)、药物从中央室消除的一级速率常数(k₁₀)、药物从中央室向周边室转运的一级速率常数(k₁₂)、药物从周边室向中央室转运的一级速率常数(k₂₁)等药动学参数与挥发油组的差异均具有统计学意义(P<0.05或P<0.01)。药动学结果表明微囊有效延长了桂枝、当归挥发油在体内滞留时间，促进药物在体内的吸收，口服相对生物利用度提高至2.62倍。结论 Box-Behnken设计-效应面法所建立的模型能较好地优化桂枝、当归挥发油微囊的处方工艺，具有良好预测性。处方优化后制备的微囊具有良好载药性能，提高了挥发油的生物利用度。     

CMIA、FPIA、MEIA与EMIT测定血药浓度的比较分析

目的：分析比较化学发光微粒子免疫分析法（CMIA）、荧光偏振免疫分析法（FPIA）、微粒子捕捉免疫分析法（MEIA）和酶扩大免疫分析法（EMIT）测定血清丙戊酸（VPA）、全血环孢霉素A（CsA）、血清卡马西平（CBZ）和血清地高辛（DIG）浓度的一致性。方法：通过测定高、中、低浓度质控样品,评价各方法的准确度及精密度,并对临床患者的VPA、CsA、CBZ和DIG样本进行测定,比较4种方法测定结果的相关性。结果：CMIA与EMIT（测定值为函数Y）比较,测定VPA的结果具有良好的相关性和差异性,Y_EMIT=1.172X_CMIA+0.227（r=0.97）,EMIT的测定结果比CMIA平均高17.49%。FPIA与EMIT比较,测定结果具有良好的相关性：VPA,Y_EMIT=1.259X_FPIA-4.671（r=0.97）;CsA,Y_EMIT=0.832X_FPIA+17.63（r=0.97）;CBZ,Y_EMIT=1.156X_FPIA-2.657（r=0.98）;MEIA与EMIT比较,测定结果有相关性：DIG,Y_EMIT=0.634X_MEIA+0.018（r=0.91）;其中CsA的EMIT测定结果比FPIA平均低2.08%,DIG的EMIT测定结果比MEIA平均低35.91%,而VPA的EMIT测定结果比FPIA平均高16.83%、CBZ的EMIT测定结果比FPIA平均高3.07%。结论：CMIA测定VPA血药浓度、FPIA测定VPA、CsA、CBZ及MEIA测定DIG血药浓度与EMIT的测定结果,存在差异性（P<0.05）,临床应用中应予以关注并作相应调整。     

RP-HPLC法测定田七痛经胶囊中阿魏酸、藁本内酯、欧当归内酯A

目的 建立高效液相色谱法测定田七痛经胶囊中阿魏酸、藁本内酯、欧当归内酯A的方法。方法 选用Thermo Acclaim C₁₈色谱柱,Thermo SCIENTIFICSyncronis C₁₈色谱柱;检测波长为321、280 nm;体积流量1.0 mL/min;柱温35℃结果 阿魏酸、藁本内酯、欧当归内酯A的质量浓度与峰面积分别在1.12～112.30、1.33～132.60、0.96～95.50 μg/mL呈良好的线性关系;回归方程分别为Y=46 335 540 X+44 186.71（r=0.998）,Y=14 514 060 X+8 715.27（r=0.999）,Y= 22 031 250 X+16 472.10（r=0.999）。结论 该方法准确,简便,灵敏,可作为田七痛经胶囊质量控制的方法。     

硅橡胶质量参数与氟尿嘧啶植入剂释放度的相关性研究

目的 分析硅橡胶分子量及黏度特性对氟尿嘧啶植入剂释放度的影响。方法 依据GN/T21863-2008标准和《中国药典》对不同批号硅橡胶的分子量分布和黏度进行检测,记录数均分子量、分子量分布和黏度,采用相同制剂工艺制备20份不同硅橡胶的小试样品,依据国家药品标准WS1-（X-103）-2005Z对小试样品的释放度进行检测,以数均分子量（X₁）、分子量分布（X₂）和黏度（X₃）作为X变量,以120 h释放度结果作为Y变量,使用Minitab 16.0软件进行多元回归分析,确定硅橡胶关键质量参数。结果 多元回归分析表明,数均分子量和黏度参数是关键质量参数（P<0.05）,分子量分布为非关键质量参数（P>0.05）;120 h释放度的线性回归方程：Y=-0.3+3.76 X₁+0.267X₃。结论 硅橡胶数均分子量和黏度是影响氟尿嘧啶植入剂释放度的关键质量参数,产品生产过程中应依据制剂工艺参数对硅橡胶的制备进行严格控制,从而最大程度降低硅橡胶对产品质量稳定性造成的影响。     

HPLC法测定癃闭舒片中补骨脂素和异补骨脂素

目的 建立癃闭舒片中补骨脂素和异补骨脂素的定量方法。方法 对国内3个企业生产的6个批次的癃闭舒片,采用HPLC法检测,Agilent TC-C₁₈(2)色谱柱(250 mm×4.6 mm,5μm),流动相是甲醇-水(43:57),体积流量1.0 mL/min,检测波长为246 nm,柱温30℃。结果 补骨脂素回归方程为:Y=84.44X+9.994,r=0.9999(n=12)。异补骨脂素回归方程为:Y=82.434X+8.8952,r=0.9999(n=12)。补骨脂素和异补骨脂素的线性范围均在4.04~151.5μg。结论 本方法操作简便、准确、专属性强、稳定,可用于癃闭舒片中补骨脂素和异补骨脂素的含量测定。     

葫芦素B-聚乳酸-羟基乙酸共聚物载药纳米粒的构建与药效学评价

目的 以聚乳酸-羟基乙酸共聚物（PLGA）作为纳米制剂载体材料将葫芦素B制备成纳米粒,并考察其对HepG2肝癌细胞的抑制效果。方法 使用乳化溶剂蒸发法制备葫芦素B-PLGA载药纳米粒,以PLGA浓度（X₁）、PVA浓度（X₂）和药物浓度（X₃）作为考察因素,以载药纳米粒的粒径大小（Y₁）和包封率（Y₂）作为评价指标,应用中心复合设计-效应面法优化葫芦素B-PLGA载药纳米粒处方;测定了纳米粒的粒径分布和Zeta电位值,通过透射电镜观察其微观形态,并考察了葫芦素B-PLGA载药纳米粒的体外药物释放特性;比较了葫芦素B与葫芦素B-PLGA载药纳米粒对HepG2肝癌细胞的抑制效果。结果 葫芦素B-PLGA载药纳米粒的最优处方组成为：PLGA浓度为9.0%,PVA浓度为2.0%,药物浓度为4.5%,制备的纳米粒粒径为（145.4±15.8） nm,Zeta电位值为（-7.6±0.8） mV;透射电镜下可观察到纳米粒表面光滑,分布均匀;葫芦素B-PLGA载药纳米粒释药前期出现突释,后期平缓,48 h药物释放达到86%;葫芦素B-PLGA载药纳米粒对HepG2肝癌细胞的抑制作用显著高于葫芦素B。结论 葫芦素B-PLGA载药纳米粒可延缓药物释放,提高对HepG2肝癌细胞的抑制活性,为进一步临床研究奠定实验基础。     

HPLC同时测定丹酚酸B和阿魏酸的含量

目的 建立HPLC同时测定丹酚酸B和阿魏酸的方法。方法 色谱柱ODS-C₁₈(4.6 mm×250 mm,5 μm)柱,流动相：甲醇-乙腈-甲酸-水,检测波长为286 nm,流速0.8 mL·min^-1。结果 丹酚酸B浓度在5.40~43.25 μg·mL^-1,阿魏酸浓度在3.37~27.00 μg·mL^-1内线性关系良好。丹酚酸B和阿魏酸的线性方程分别为：Y=0.971 1X-2.215 4,r=0.999 8,Y=0.415 9X-0.450 7,r=0.999 9;平均回收率分别为98.4%,98.7%;RSD分别为3.39%,1.49%。结论 本法在检测丹酚酸B和阿魏酸时有较好的专属性,灵敏度高,重复性好,且样品处理简单、容易操作,可以作为丹参和当归复方制剂的质量检测方法。     

原子吸收光谱法和原子荧光光谱法测定蜂产品中的重金属残留量

目的 建立不同种类蜂产品中铅、砷、汞的重金属残留量的检测方法。方法 采用微波消解法处理蜂产品,通过选择最佳消解条件和测定条件,利用石墨炉原子吸收光谱法测定蜂产品中铅含量,和利用原子荧光光谱法测定蜂产品中砷、汞含量,并对测定方法进行方法学考察。结果 铅、砷、汞测定方法线性关系分别为Y=0.003 04X+0.001 31（r=0.999 6）、Y=88.645 1X＋2.563 8（r=0.999 9）、Y=552.113 2X-6.169 5（r=0.999 6）,RSD均<3%,回收率分别为98.2%,96.3%,93.8%,测定结果分别为0.003~4.203,0~0.192,0~0.097 6 mg·kg^-1。结论 不同种类蜂产品中重金属含量不同,其中铅含量最高,本方法适用于同时检测蜂产品中多种重金属残留。     

HPLC-荧光法测定人血浆中羟基喜树碱的两种构型及其相互间的转化

目的 建立高效液相色谱法(HPLC)测定人血浆中羟基喜树碱两种活性成分盐型羟基喜树碱(C-HCPT)和酯型羟基喜树碱(L-HCPT)含量的方法,并且对两者之间的相互转化进行了初步研究。方法 采用HPLC-荧光法,Lichrospher C₁₈色谱柱,流动相为乙腈-0.075 mol·L^-1醋酸铵缓冲液(32∶68,pH 6.4),流量1.0 ml·min^-1,检测器激发波长为363 nm,发射波长为530 nm,内标法计算药物浓度。结果 人血浆样品中C-HCPT、L-HCPT峰分离良好,内源性杂质不干扰样品峰,最低检测浓度均为5 ng·ml^-1。C-HCPT、L-HCPT浓度范围在15～2000 ng·ml^-1间呈线性相关,回归方程分别为Y₁=9.393×10^-4X₁-9.1×10^-6和Y₂=1.0207×10^-3X₂-3.4×10^-6,相关系数分别为r₁=0.9997和r₁=0.9998,相对回收率分别为96.79%～119.64%和100.23%～112.93%,日内和日间变异均小于10%。两者之间的转化具有一定规律性;C-HCPT标准血样-20℃冻存20 d稳定,L-HCPT标准血样的稳定性有待进一步研究。结论 本方法专属性强，灵敏、可靠，适用于HCPT 类制剂给药后血药浓度的监测和体内的药代动力学特征研究；有关两者相互转化的机制及L-HCPT 稳定性问题尚待进一步深入研究。     

Statistical optimization of controlled release microspheres containing cetirizine hydrochloride as a model for water soluble drugs

Abstract

The purpose was to improve the encapsulation efficiency of cetirizine hydrochloride (CTZ) microspheres as a model for water soluble drugs and control its release by applying response surface methodology. A 3³ Box–Behnken design was used to determine the effect of drug/polymer ratio (X₁), surfactant concentration (X₂) and stirring speed (X₃), on the mean particle size (Y₁), percentage encapsulation efficiency (Y₂) and cumulative percent drug released for 12?h (Y₃). Emulsion solvent evaporation (ESE) technique was applied utilizing Eudragit RS100 as coating polymer and span 80 as surfactant. All formulations were evaluated for micromeritic properties and morphologically characterized by scanning electron microscopy (SEM). The relative bioavailability of the optimized microspheres was compared with CTZ marketed product after oral administration on healthy human volunteers using a double blind, randomized, cross-over design. The results revealed that the mean particle sizes of the microspheres ranged from 62 to 348?µm and the efficiency of entrapment ranged from 36.3% to 70.1%. The optimized CTZ microspheres exhibited a slow and controlled release over 12?h. The pharmacokinetic data of optimized CTZ microspheres showed prolonged t_max, decreased C_max and AUC_0–∞ value of 3309?±?211 ng?h/ml indicating improved relative bioavailability by 169.4% compared with marketed tablets.     

Chitosan microparticle preparation for controlled drug release by response surface methodology

The objectives were to investigate the effects of formulation variables on the release of drug and to optimize the formulation of chitosan microparticles loaded with drug for controlled release using response surface methodology. Chitosan microparticles were prepared by dropping a chitosan solution into sodium tripolyphosphate (TPP) through ionic cross-linking. The release behaviour of felodipine as a model drug was affected by preparation variables. A central composite design was used to evaluate and optimize the effect of preparation variables, chitosan concentration (X₁), the pH of the TPP solution (X₂) and cross-linking time (X₃) on the cumulative per cent drug release (Y) in 24 h. Chitosan concentration and cross-linking time affected negatively the release of felodipine, while the pH of the TPP did so positively and was the highest influential factor. The optimum rate of drug release, 100% in 24 h, was achieved at 1.8% chitosan concentration, a pH 8.7 for the TPP solution and 9.7 min cross-linking time.     

Response Surface Methodology to Investigate the Iontophoretic Delivery of Tacrine Hydrochloride

No HeadingPurpose. The objective of this work was to apply response surface approach to investigate the main and interaction effects of delivery parameters for iontophoretic delivery of tacrine HCl in vitro.Methods. Iontophoresis was used to deliver tacrine HCl across rat skin. Experiments were performed according to Box-Behnken design to evaluate effects of drug concentration (X₁), current density (X₂), and donor buffer molarity (X₃) on cumulative drug delivered in 24 h (Y₁), 6 h (Y₂), iontophoretic flux (Y₃), and post-iontophoretic flux (Y₄).Results. Mathematical model for Y₁ was Y₁ = 0.653 + 0.163 * X₁ + 0.456 * X₂ – 0.156 * X₃ + 0.190 * X₁X₂ + 0.139* X₃X₃. Response surface plot indicated that at low level of X₂ (0.1mA/cm²), X₁ had little effect on Y₁. However, at high level of X₂ (0.5 mA/cm²), Y₁ significantly increased from 0.75 mg/cm² to 1.46 mg/cm² when X₁ increased from 1% to 9%. Regression equations predicted responses for Y₁ to Y₄, for optimal formulation, which were in reasonably good agreement with experimental values.Conclusions. Experimental design methodology revealed an interaction between drug concentration and current density, which would have been difficult to predict from one factor at a time classic experimental approach.     

Optimization and evaluation of lyophilized fenofibrate nanoparticles with enhanced oral bioavailability and efficacy

Abstract

The objective of this study was to enhance physiochemical properties as well as oral bioavailability of the poorly water soluble drug fenofibrate (FB), through preparation of amorphous solid dispersions (ASDs). ASDs were prepared via freeze drying using polyvinylpyrrolidone (PVP) K30 and poloxamer 188 as hydrophilic carriers. Formulations were optimized by 3² full factorial design (FFD) with PVP-K30 level (X₁) and poloxamer 188 level (X₂) as independent variables and particle size (Y₁), zeta potential (Y₂), drug content (Y₃) and dissolution rate (T90, [Y₄]) as dependent variables. Optimized FB nanoparticles were physicochemically evaluated and formulated into lyophilized sublingual tablets. Pharmacokinetic, pharmacodynamics and histological finding of optimized formulation were performed on rabbits. Y₁ and Y₄ were significantly affected by independent variables while Y₂ and Y₃ were not affected. Physicochemical characterization showed the drug was in amorphous state, nanometer range and pharmacophore of FB was preserved. Administration of optimized FB tablets to rabbits with fatty liver led to significant reduction (p?<?0.001) in serum lipids. Moreover, histological analysis of liver specimens confirmed the improved efficacy in animals with fatty liver. In this study, we confirmed that ASDs of FB had beneficial effects on managing fatty liver and serum lipids level in hyperlipidemic rabbits.     

Application of Box-Behnken design in understanding the quality of genistein self-nanoemulsified drug delivery systems and optimizing its formulation

The purpose of the present study was to understand the effect of formulation variables of self- nanoemulsified drug delivery systems (SNEDDS) on the rapid dissolution of a model drug, genistein (GN). A three-factor, three-level Box-Behnken design was used to explore the main and interaction effect of several independent formulation variables including the amount of Maisine 35-1 and Labrafac Lipophile WL 1349 (1:1, w/w) (X₁), Cremophor EL and Labrasol (3:1, w/w) (X₂), and Transcutol P (X₃). Droplet size (Y₁), turbidity (Y₂), and dissolution percentage of GN after 5 (Y₃) and 30 (Y₄) min were the dependent variables. A mathematical relationship, Y₃?=???89.3447?+?5.9524X₁?+?1.0683X₂?+?0.462X₃???0.0825X₁²???0.0075X₂²???0.0009X₃²?+?0.0104X₁X₂ ??0.0113X₁X₃?+?0.0009X₂X₃ (r2?=?0.9604), was obtained to explain the effect of all factors and their co-linearities on the dissolution of GN at 5?min. Formulation optimization was then performed to maximize dissolution percentage of GN at 5?min (Y₃). The optimized formulation was predicted to dissolution 93.34% of GN at 5?min, when X₁, X₂ and X₃ values were 37.1, 101.7 and 77.3?mg, respectively. A new batch was prepared according to the optimized formulation, and the observed and predicted values of Y₃ were in close agreement. In conclusion, the Box-Behnken experimental design allowed us to understand the effect of formulation variables on the rapid dissolution of GN from SNEDDS, and optimize the formulation to obtain a rapid drug dissolution at 5?min.     

Fabrication and evaluation of captopril modified-release oral formulation

The present research was directed towards fabrication of modified-release captopril oral formulation. A 3² full factorial design was employed for optimization using captopril to Compritol® ATO 888 ratio (X₁) and extragranular fraction of ethyl cellulose (X₂) as independent variables. The percentage drug released in 1?h (Y₁) and the time required to release 80% of the drug (Y₂) were selected as dependent variables. Eutectic blend of camphor and menthol was used as a solvent to facilitate the drug distribution in matrix. The optimized batch containing 50?mg captopril, 160?mg Compritol® ATO 888 and 220?mg ethyl cellulose was formulated by overlapping the contour plots of Y₁ and Y₂. The responses Y₁ and Y₂ of optimized batch were 25% and 520?min, respectively. The kinetics of drug release was best explained by Korsmeyer-Peppas model. The results of artificial neural network were superior in prediction power than the factorial design for both the responses (Y₁ and Y₂).     

Optimization of minoxidil microemulsions using fractional factorial design approach

The objective of this study was to apply fractional factorial and multi-response optimization designs using desirability function approach for developing topical microemulsions. Minoxidil (MX) was used as a model drug. Limonene was used as an oil phase. Based on solubility, Tween 20 and caprylocaproyl polyoxyl-8 glycerides were selected as surfactants, propylene glycol and ethanol were selected as co-solvent in aqueous phase. Experiments were performed according to a two-level fractional factorial design to evaluate the effects of independent variables: Tween 20 concentration in surfactant system (X₁), surfactant concentration (X₂), ethanol concentration in co-solvent system (X₃), limonene concentration (X₄) on MX solubility (Y₁), permeation flux (Y₂), lag time (Y₃), deposition (Y₄) of MX microemulsions. It was found that Y₁ increased with increasing X₃ and decreasing X₂, X₄; whereas Y₂ increased with decreasing X₁, X₂ and increasing X₃. While Y₃ was not affected by these variables, Y₄ increased with decreasing X₁, X₂. Three regression equations were obtained and calculated for predicted values of responses Y₁, Y₂ and Y₄. The predicted values matched experimental values reasonably well with high determination coefficient. By using optimal desirability function, optimized microemulsion demonstrating the highest MX solubility, permeation flux and skin deposition was confirmed as low level of X₁, X₂ and X₄ but high level of X₃.     

Multiple response optimisation of processing and formulation parameters of pH sensitive sustained release pellets of capecitabine for targeting colon

Purpose: To optimise the Eudragit/Surelease^®-coated pH-sensitive pellets for controlled and target drug delivery to the colon tissue and to avoid frequent high dosing and associated side effects which restrict its use in the colorectal-cancer therapy.

Methods: The pellets were prepared using extrusion-spheronisation technique. Box–Behnken and 3² full factorial designs were applied to optimise the process parameters [extruder sieve size, spheroniser-speed, and spheroniser-time] and the coating levels [%w/v of Eudragit S100/Eudragit-L100 and Surelease^®], respectively, to achieve the smooth optimised size pellets with sustained drug delivery without prior drug release in upper gastrointestinal tract (GIT).

Results: The design proposed the optimised batch by selecting independent variables at; extruder sieve size (X₁?=?1?mm), spheroniser speed (X₂?=?900 revolutions per minute, rpm), and spheroniser time (X₃?=?15?min) to achieve pellet size of 0.96?mm, aspect ratio of 0.98, and roundness 97.42%. The 16%w/v coating strength of Surelease^® and 13%w/v coating strength of Eudragit showed pH-dependent sustained release up to 22.35?h (t_99%). The organ distribution study showed the absence of the drug in the upper part of GIT tissue and the presence of high level of capecitabine in the caecum and colon tissue. Thus, the presence of Eudragit coat prevent the release of drug in stomach and the inner Surelease^® coat showed sustained drug release in the colon tissue.

Conclusion: The study demonstrates the potential of optimised Eudragit/Surelease^®-coated capecitabine-pellets for effective colon-targeted delivery system to avoid frequent high dosing and associated systemic side effects of drug.     

Transdermal agomelatine microemulsion gel: pyramidal screening,statistical optimization and in vivo bioavailability

Agomelatine is a new antidepressant having very low oral drug bioavailability less than 5% due to being liable to extensive hepatic 1st pass effect. This study aimed to deliver agomelatine by transdermal route through formulation and optimization of microemulsion gel. Pyramidal screening was performed to select the most suitable ingredients combinations and then, the design expert software was utilized to optimize the microemulsion formulations. The independent variables of the employed mixture design were the percentages of capryol 90 as an oily phase (X₁), Cremophor RH40 and Transcutol HP in a ratio of (1:2) as surfactant/cosurfactant mixture ‘S_mix’ (X₂) and water (X₃). The dependent variables were globule size, optical clarity, cumulative amount permeated after 1 and 24?h, respectively (Q1 and Q₂₄) and enhancement ratio (ER). The optimized formula was composed of 5% oil, 45% S_mix and 50% water. The optimized microemulsion formula was converted into carbopol-based gel to improve its retention on the skin. It enhanced the drug permeation through rat skin with an enhancement ratio of 37.30 when compared to the drug hydrogel. The optimum ME gel formula was found to have significantly higher C_max, AUC _0–24?h and AUC_0–∞ than that of the reference agomelatine hydrogel and oral solution. This could reveal the prosperity of the optimized microemulsion gel formula to augment the transdermal bioavailability of agomelatine.     

Box-behnken design for the optimization of formulation variables of indomethacin coprecipitates with polymer mixtures

Numerous reports explain the dissolution release mechanisms and certain matrix type formulations follow the Higuchi's square root of time model. Earlier screening experiments have shown that compression of indomethacin coprecipitates prepared using Eudragit polymer mixtures yielded matrix tablets which release 80% of the drug in 24 h. The present study deals with optimization of formulation variables to improve dissolution characteristics of the matrix formulation. A three-factor, three-level Box-Behnken design with drug to polymer ratio (X₁), polymer to polymer ratio (X₂) and solvent ratio (X₃) as the independent variables were selected for the study. The dependent variable was cumulative percent of drug released in 24 h. As a novel approach, constraints were placed on the dependent variable such that the ideal release characteristics of a matrix formulation would be obtained for the 24-h release formulation. Based on the experimental design, different indomethacin release rates and profiles were obtained. The dependent and independent variables were related using mathematical relationships and surface response plots. The model predicted a 100.7% release with the X₁, X₂ and X₃ levels of 7.813, 0.9586 and 1.5, respectively. The optimized formulation prepared according to predicted levels provided release rates which were close to predicted values. Also, the observed and predicted response values fell in the range of calculated values as obtained from the Higuchi's model. Further, the optimized formulation was compared with solid dispersions and physical mixtures. All the formulations were characterized by X-ray diffraction, IR DSC and dissolution studies.