Development of a predictive in vitro dissolution for clarithromycin granular suspension based on in vitro-in vivo correlations

The objective of this study was to evaluate the in vitro behavior of different clarithromycin granular suspensions based on a developed in vitro-in vivo correlation model, using one reference and two test formulations. In vitro release rate data were obtained for each product using the USP apparatus II, operated at 50?rpm under different pH conditions. The dissolution efficiency was used to analyze the dissolution data. In vivo study was performed on six healthy male volunteers under fasting condition. Correlation was made between in vitro release and in vivo absorption. A linear model was developed using percent absorbed data versus percent dissolved data from the three products. Dissolution condition of 0.1N HCl for 1?h and then phosphate buffer at pH 6.8 was found to be the most discriminating dissolution method. Rate of absorption for the reference as estimated by Wagner-Nelson deconvolution was correlated with in vitro release with a correlation coefficient of 0.99. The in vivo results for the two test products were compared to the predicted values using the reference model with a correlation coefficient of 0.94. Furthermore, multiple level C correlations were obtained for some pharmacokinetic parameters with the corresponding in vitro kinetic parameters with correlation coefficients exceeding 0.90. Moreover, the interpretation of the in vitro and in vivo data with reference to formulations was discussed.     

Extended release dosage form of glipizide: development and validation of a level A in vitro-in vivo correlation

Defining a quantitative and reliable relationship between in vitro drug release and in vivo absorption is highly desired for rational development, optimization, and evaluation of controlled-release dosage forms and manufacturing process. During the development of once daily extended-release (ER) tablet of glipizide, a predictive in vitro drug release method was designed and statistically evaluated using three formulations with varying release rates. In order to establish internally and externally validated level A in vitro-in vivo correlation (IVIVC), a total of three different ER formulations of glipizide were used to evaluate a linear IVIVC model based on the in vitro test method. For internal validation, a single-dose four-way cross over study (n=6) was performed using fast-, moderate-, and slow-releasing ER formulations and an immediate-release (IR) of glipizide as reference. In vitro release rate data were obtained for each formulation using the United States Pharmacopeia (USP) apparatus II, paddle stirrer at 50 and 100 rev. min(-1) in 0.1 M hydrochloric acid (HCl) and pH 6.8 phosphate buffer. The f(2) metric (similarity factor) was used to analyze the dissolution data. The formulations were compared using area under the plasma concentration-time curve, AUC(0-infinity), time to reach peak plasma concentration, T(max), and peak plasma concentration, C(max), while correlation was determined between in vitro release and in vivo absorption. A linear correlation model was developed using percent absorbed data versus percent dissolved from the three formulations. Predicted glipizide concentrations were obtained by convolution of the in vivo absorption rates. Prediction errors were estimated for C(max) and AUC(0-infinity) to determine the validity of the correlation. Apparatus II, pH 6.8 at 100 rev. min(-1) was found to be the most discriminating dissolution method. Linear regression analysis of the mean percentage of dose absorbed versus the mean percentage of in vitro release resulted in a significant correlation (r(2)>or=0.9) for the three formulations.     

Correlation of ‘in vitro’ release and ‘in vivo’ absorption characteristics of rifampicin from ethylcellulose coated nonpareil beads

The purpose of this study was to investigate the possibility to develop different levels of correlation between in vitro dissolution parameters and in vivo pharmacokinetic parameters for three rifampicin formulations. A level A correlation of in vitro release and in vivo absorption could be obtained for individual plasma level data by means of the Wagner and Nelson method. Linear correlation could be obtained when percent dose released in vitro was plotted vs percent dose absorbed in vivo with correlation coefficients between 0.954, 0.983 and 0.997 for the formulations studied. A second level correlation between mean in vitro dissolution time (MDT) and mean in vivo residence time (MRT) was performed with a correlation coefficient of 0.536, 0.420 and 0.335. Finally, it was also possible to establish a good in vitro–in vivo correlation when the T_50%hrs (time taken to release 50% of rifampicin) in vitro and C_max, T_max or AUC in vivo were compared.     

Once-a-day controlled-release dosage form of divalproex sodium II: development of a predictive in vitro drug release method

During formulation design of a once-daily controlled release matrix system of divalproex sodium, the in vitro dissolution test (USP II, 100 rpm, pH 6.8 buffer) was found to result in release rates that were slower than in vivo absorption. The test method also did not sufficiently discriminate formulations with different in vivo absorption rates. To develop an in vitro method that is directly correlated with in vivo absorption, statistically designed studies were carried out to investigate the effects of various in vitro testing variables on drug release using USP dissolution apparatuses. The variables studied included agitation intensity, apparatus, pH, surfactant and ionic strength of the dissolution medium. Experimental data were analyzed using ANOVA. In vitro/in vivo correlation was tested based on the hypothesis that the same linear regression equation holds for three formulations with different release rates. A mixed effects model was used in which the dependence among observations from the same subject was taken into account. Factorial studies indicated that higher pH, addition of sodium lauryl sulphate (SLS) to the dissolution medium, and higher agitation intensity increased the release rate from the matrix tablet. Use of SLS not only lead to increased release rates that are more comparable to in vivo absorption rates, but also improved differentiation among formulations with varying release rates. Furthermore, drug release was also affected by interactions among the variables studied. Statistical analysis indicated that a combination of higher SLS concentration and lower pH provided enhanced differentiation between release profiles of the fast and slow releasing formulations. Based on the above findings, a new set of testing conditions was identified and demonstrated to be predictive of in vivo drug absorption for various controlled release formulations of divalproex sodium. The new method uses USP Apparatus II operating at 100 rpm in 500 mL of 0.1 N HCl for 45 min followed by 900 mL of 0.05 M phosphate buffer containing 75 mM SLS, pH 5.5, 37 +/- 0.5 degrees C. In conclusion, adjusting dissolution testing conditions to match the behavior of the formulations in vitro with that in vivo is a useful approach in identifying a predictive method in development of in vitro-in vivo correlation.     

Release and absorption characteristics of chlorphenesin carbamate sustained-release formulations: In vitro-in vivo and in vivo dog-human correlations

The bioavailability of chlorphenesin carbamate (CPC) in sustained-release (SR) formulations exhibiting different in vitro release characteristics in dogs and humans was examined using formulations tested previously in the in vitro dissolution method. The human-dog correlation of the bioavailability of SR formulations was examined under fasting conditions. Pharmacokinetic analysis using the Wagner-Nelson procedure revealed sustained-release absorption characteristics for the SR formulations, with the exception of the immediate-release (IR) formulation as control in dogs and humans. For each of the SR formulations tested, regression analysis results of the percentage of CPC absorbed in human against that in dogs, at corresponding times, indicated a high correlation. Moreover, the correlation of the dissolution rates and bioavailabilities of these formulations in humans was also examined. Although the in vitro CPC release profiles from the SR formulations were smooth and controlled, they were too rapid when compared with the in vivo human data. However, the rank order was exactly the same between in vivo and in vitro data, and a good relationship was found after time scaling of the release data. These data imply that the release characteristics of CPC after changing of the formulations could be evaluated using the in vitro dissolution method or dogs as an animal model in place of human studies.     

克拉霉素缓释胶囊释放度与体内吸收度相关性的研究

摘要目的：研究两种释药机理的克拉霉素缓释胶囊试验制剂体内一体外相关性，建立与体内吸收相关的释放度测定法。方法：在不同pH介质中测定克拉霉素缓释胶囊的体外释放度。采用LC-MS-MS测定健康志愿者单剂量交叉口服250mg克拉霉素胶囊(F-1和F-2)后血药浓度，以Wagner—Nelson法计算药物的体内吸收百分数。以体外释放百分率对体内吸收百分数在相应的时间点进行相关性分析。结果：表明缓释胶囊F-1在pH5．0介质中释放百分率与体内吸收百分数相关，相关系数为0．9984，缓释胶囊F-2在pH6．0介质中释放百分率与体内吸收百分数相关，相关系数为0．9939。结论：经相关性检验，两种克拉霉素缓释胶囊的体外释放与体内吸收为水平A相关。F-1在体内的吸收程度高于F-2，为F-1的处方筛选提供了理论依据。     

In vitro-in vivo correlation (IVIVC) models for metformin after administration of modified-release (MR) oral dosage forms to healthy human volunteers

The objective of the current study was to develop and evaluate the internal predictability for level C and A in vitro-in vivo correlation (IVIVC) models for prototype modified-release (MR) dosage forms of metformin. In vitro dissolution data for metformin were collected for 22 h using a USP II (paddle) method. In vivo plasma concentration data were obtained from 8 healthy volunteers after administration of immediate-release (IR) and MR dosage forms of metformin. Linear level C IVIVC models were developed using dissolution data at 2.0 and 4.0 h and in vitro mean dissolution time (MDT). A deconvolution-based level A model was attempted through a correlation of percent in vivo input obtained through deconvolution and percent in vitro dissolution obtained experimentally. Further, basic and extended convolution level A IVIVC models were attempted for metformin. Internal predictability for the IVIVC models was assessed by comparing observed and predicted values for C(max) and AUC(INF). The results suggest that highly predictive level C models with prediction errors (%PE) of <5% could be developed. Mean percent in vivo input for metformin was incomplete from all formulations and did not exceed 35% of dose. The deconvolution-based level A models for all MR formulations were curvilinear. However, a unique IVIVC model applicable to all MR formulations could not be developed using the deconvolution approach. The basic convolution level A model, which used in vitro dissolution as the in vivo input, had %PE values as high as 103%. Using an extended convolution approach, which modeled the absorption of metformin using a Hill function, a level A IVIVC model with %PE as low as 11% was developed. In conclusion, the current work indicates that level C and A IVIVC models with good internal predictability may be developed for a permeability- and absorption window-limited drug such as metformin.     

Use of an in vitro absorption model system for predicting sustained release of verapamil.

It is shown that it is possible to characterize sustained release formulations in vitro using not only dissolution data but also an absorption model system. The mean dissolution time (MDT) has been shown to be a suitable parameter for evaluating sustained release formulations in vitro. t1/2 and mean residence time (MRT) have been shown to be convenient pharmacokinetic parameters for characterizing sustained release formulations. For comparing in vitro and in vivo results the quotients MDT normal/MDT retard and MRT normal/MRT retard do seem to be useful.     

Development of level A,B and C in vitro-in vivo correlations for modified-release levosimendan capsules

The aim of this study was to investigate the possibility of developing different levels of correlation between in vitro release and in vivo absorption rate for four modified-release levosimendan capsule formulations. Differences and similarities in the in vitro dissolution curves were compared with pharmacokinetic parameters describing absorption rate. Formulations F, G, H and I differed in the amounts of the delaying excipients alginic acid and HPMC. In vitro release rate was studied by the USP basket method using the following conditions: pH 5.8 or 7.4 and a rotation speed of 50 or 100 rpm. In vivo bioavailability was tested in nine healthy male volunteers and the fractions absorbed were calculated by the Wagner-Nelson method. Dissolution conditions pH 5.8 and a rotation speed of 100 rpm predicted best the similarities and differences in absorption rates among different formulations, and levels C and B correlation coefficients were 0.85 and 0.97, respectively. For formulation H level A correlation (r=0.997) was found when in vitro lag time was 0.2 h and time scale factor 1.9. This study indicated that dissolution tests developed can be used as a surrogate for human bioequivalence studies, for development processes of final commercial products, to ensure batch to batch bioequivalence and in the future in possible scale-up and post approval change cases for modified-release levosimendan formulation H.     

Preparation and in vitro/in vivo evaluation of sustained-release venlafaxine hydrochloride pellets

The objective of this study was to prepare different venlafaxine hydrochloride sustained-release products and to elucidate the influence of composition of the coating film on the in vitro drug release profiles and in vivo pharmacokinetics. Pellets were prepared by a standardized process of extrusion/spheronization. A selected fraction size (0.8-1.0 mm diameter) of pellets of each formulation was coated with Eudragit NE30D or ethylcellulose (10 cps). Many efforts have been made to tailor drug release rate by choosing different coating materials, different percent of pore forming components and coating weight variation to achieve a desired sustained-release effect. The dissolution studies were performed and data were analyzed in terms of cumulative release as a function of time. The influence on the release of venlafaxine from sustained-release capsules was observed in dissolution media of different pH and gradient pH. Scanning electron microscope (SEM) micrographs revealed morphological changes of the pellet coating surface which were related to in vitro drug release profiles. The relative bioavailability for Formulation 1 and Formulation 2 was evaluated in six healthy beagle dogs after oral administration in a fast state using sustained-release capsules (Effexor XR) as a reference. The results suggested that Formulation 1 and Formulation 2 both had better bioavailability compared with Effexor XR. It could be found that there existed quite difference in the in vivo release and oral absorption performances, despite the similar in vitro drug release behavior for the two formulations. It might be attributable to complex in vivo environment and then variation in the release behavior. Thus differences in the film micro-structure and surface roughness caused by aqueous dispersion and organic solvent coating techniques strongly influence the in vivo release and oral absorption performances.     

Organic acids as excipients in matrix granules for colon-specific drug delivery.

Interest exists in developing site-specific systems for release of a drug in the lower part of the small intestine or in the colon. The aim of this study was to investigate whether drug release rates from enteric matrix granules could be influenced by using organic acids as excipients. Ibuprofen was used as a model drug and Eudragit S and Aqoat AS-HF as enteric polymers. The dissolution rates of the drug were investigated at different levels of pH (5.8, 6.8 and 7. 4). Drug absorption was studied in bioavailability tests in healthy volunteers. In vitro/in vivo correlation was also investigated. It was concluded that although inclusion of an organic acid in a formulation retarded in vitro release of the model drug, no corresponding effect was evident in in vivo studies. Bioavailability tests are therefore important early on during development of new dosage forms or formulations. Although no correlation between in vitro and in vivo results was generally evident correlation could be demonstrated for individual formulations following mathematical transformation of data. Copyright     

盐酸地尔硫控释胶囊人体内外相关性

目的:考察盐酸地尔硫控释胶囊(DTZ-CRC)的体外释放度与体内吸收的相关性.方法:测定DTZ- CRC在不同pH释放介质中的释放度;10名男性健康志愿者po 60mg DTZ-CRC,HPLC法测定血药浓度,按照Wagner-Nelson公式计算药物吸收分数.结果:不同释放介质中药物的体外释放度与体内吸收分数的相关系数r分别为0.984 8、0.986 7和0.982 8.结论:DTZ-CRC的体外释放度与体内吸收具有显著的相关性.     

三七总皂苷缓释片的释放性能及体内外相关性研究

目的评价三七总皂苷缓释片的体外释放特性、体内药物动力学及体内外相关性。方法以磷酸盐缓冲液为释放介质,考察三七总皂苷缓释片的体外释放特性。以6只Beagle犬为实验动物,测定口服给予缓释片后血药浓度的变化,计算药代动力学参数,并对体外累积释放度和体内累积吸收百分率进行回归,考察其体内外相关性。结果三七总皂苷缓释片体外药物释放具有明显的缓释特性;与普通片相比,在Beagle犬体内的达峰时间延长,峰浓度降低,平均滞留时间延长,也具有明显的缓释特性。结论制得的三七总皂苷缓释片达到了缓慢释放药物的目的,并且其体内外参数间有明显的相关性。     

In-vitro and in-vivo correlation for two gliclazide extended-release tablets

The aim of this study was to perform an in-vitro-in-vivo correlation (IVIVC) for two 60-mg gliclazide extended-release formulations (Fast and Slow release) given once a day and to compare their plasma concentrations over time. In-vitro release rate data were obtained for each formulation using the USP apparatus II, paddle stirrer at 50 and 100 rev min(-1) in 0.1 M HCl and pH 7.4 phosphate buffer. The similarity factor (f2) was used to analyse the dissolution data. Eighteen healthy subjects participated in the study, conducted according to a completely randomized, two-way crossover design. The formulations were compared using area under the plasma concentration-time curve, AUC(0-infinity), time to reach peak plasma concentration, Tmax, and peak plasma concentration Cmax, while correlation was determined between in-vitro release and in-vivo absorption. A linear correlation model was developed using percent absorbed data versus percent dissolved data from the two formulations. Predicted gliclazide concentrations were obtained by use of a curve fitting equation. Prediction errors were estimated for Cmax and area under the curve AUC(0-infinity) to determine the validity of the correlation. 0.1 M HCl at 50 rev min(-1) was found to be the most discriminating dissolution method. Linear regression analysis of the mean percentage of dose absorbed versus the mean percentage of in-vitro release resulted in a significant correlation (r2 > 0.98) for the two formulations. An average percent prediction error for Cmax was 4.15% for Fast release and 3.99% for Slow release formulation whereas for AUC(0-infinity) it was 6.36% and 4.66% for Fast release and Slow release formulation, respectively.     

马来酸曲美布汀缓释片体外释放特征与体内J＇b~H关性研究

目的考察马来酸曲美布汀缓释片体外药物释放特征与体内外相关性。方法分别采用①水、②0．1mol／L盐酸、③0．01mol／L盐酸等三种溶剂作为释放介质,考察释放介质对释放度的影响。用Wagner—Nelson方程法计算马来酸曲美布汀缓释片在健康男性受试者体内吸收百分数,并与相应时间体外累积释放度线性回归,进行体内外相关性考察。结果马来酸曲美布汀缓释片在不同释放介质中的释放度一致,均符合零级动力学。将体内累积吸收百分数y与相应时间在0．01mol／L盐酸释放介质中的体外释放百分数X进行线性回归（n=7）,回归方程为Y=1．0093x一0．3329,r：0．9600（P=0．000601〈0．001）,表明具有良好的体内外相关性,呈A级相关。结论马来酸曲美布汀缓释片的释放度不受三种释放介质影响,释药恒速。体外释放累积百分数与体内吸收百分数呈A级相关。     

Investigation on different levels of in vitro-in vivo correlation: gemfibrozil immediate release capsule

Gemfibrozil is a practically water-insoluble, high-dose drug. It represents a typical drug with dissolution rate controlled bioavailability. The aim of this study was to select a dissolution condition for gemfibrozil immediate release capsules, resulting in the best in vitro/in vivo correlation (IVIVC). Five 300 mg gemfibrozil products, including the innovator and four generic products were selected. In vitro dissolution test methods with a standard paddle, round-bottomed vessel of 1 l capacity, and potassium phosphate buffer as the dissolution medium (referred to as conditions I, II and III, respectively) were developed. The products were administered to 12 healthy volunteers and thereby different pharmacokinetic parameters were calculated. Correlations between the in vitro and in vivo calculated parameters were investigated.Of the single point parameters investigated, the best results were seen in the relation between the percent dissolved in 10, 20 and 45 min and the time to 90% dissolution from the in vitro side and the AUCs and C(max) from the in vivo side.The correlation between MRT and MDT was also investigated, and no significant correlation was found in the three above-mentioned conditions.The Wagner-Nelson method was used to calculate the percent remaining to be absorbed. Superimposition of the percent in vivo absorption and the in vitro dissolution curves was used to investigate a multiple point correlation. A remarkable superimposition between in vivo and in vitro curves in conditions I and II was observed. Copyright (c) 2008 John Wiley & Sons, Ltd.     

氯氮平漂浮缓释胶囊体内外相关性评价

目的建立氯氮平漂浮缓释胶囊体内外相关性评价模型 ,评价体内外相关性。方法利用Wanger Nelson方法和卷积模型分别评价氯氮平漂浮缓释胶囊体内外相关性。通过反卷积方法由体外释放数据得到了氯氮平漂浮缓释胶囊的体内输入函数。利用基本卷积模型和扩展卷积模型预测了氯氮平漂浮缓释胶囊体内血药浓度峰值 (Cmax)和血药浓度 时间曲线下面积值 (AUC)。结果Wanger Nelson方法的相关系数为0 9798;反卷积方法得到的体内输入值与体外释药量相关性良好 ,相关系数为 0 996。扩展卷积模型预测的Cmax和AUC值与实验值误差 <6 % ;而基本卷积模型预测值误差 >2 8%。结论氯氮平漂浮缓释胶囊体内外相关性良好。应用扩展的卷积模型能很好的预测氯氮平体内血药浓度 ,预测的体内情况可用来指导处方筛选     

以兰索拉唑肠溶胶囊为例探索模型引导的仿制药等效性替代方法

目的：本研究探索如何建立体内外相关性与生物等效性的替代方法,为药物日常质量控制及市场监管提供有效手段。方法：通过分析兰索拉唑体内吸收、分布、代谢、排泄（absorption,distribution,metabolism,excretion,ADME）过程,整合已有体外研究结果至生理药代动力学模型（physiological pharmacokinetics,PBPK）中,搭建兰索拉唑的体内药代动力学（pharmacokinetics,PK）模型,借助GastroPlus中的机制性口服吸收模型反推口服给药后在胃肠道内的释放与吸收曲线,进而构建兰索拉唑肠溶制剂的体内外相关性模型,分析现有体外溶出条件是否是与生物体相关的溶出方法。最后再通过软件开展虚拟生物等效性（bioequivalence,BE）的分析。结果：成功搭建了兰索拉唑口服给药的PK模型,模型能够较好地反映口服给药后兰索拉唑在体内的ADME过程,口服特点以及在体内的处置行为。目前法定的溶出方法与体内并非生物体相关,通过软件推测了可能生物体相关的溶出方法。同时虚拟评估了7家仿制药企业与参比制剂的生物等效性情况。结论：本研究建立了体...     

In vitro-in vivo correlation study on nimesulide loaded hydroxypropylmethylcellulose microparticles

This study involves mathematical simulation model such as in vitro-in vivo correlation (IVIVC) development for various extended release formulations of nimesulide loaded hydroxypropylmethylcellulose (HPMC) microparticles (M1, M2 and M3 containing 1, 2, and 3 g HPMC, respectively and 1 g drug in each) having variable release characteristics. In vitro dissolution data of these formulations were correlated to their relevant in vivo absorption profiles followed by predictability worth analysis of these Level A IVIVC. Nimaran was used as control formulation to validate developed formulations and their respective models. The regression coefficients of IVIVC plots for M1, M2, M3 and Nimaran were 0.834 9, 0.831 2, 0.927 2 and 0.898 1, respectively. The internal prediction error for all formulations was within limits, i.e., < 10%. A good IVIVC was found for controlled release nimesulide loaded HPMC floating M3 microparticles. In other words, this mathematical simulation model is best fit for biowaiver studies which involves study parameters as those adopted for M3 because the value of its IVIVC regression coefficient is the closest to 1 as compared to M1 and M2.     

生理药动学模型结合体外溶出试验评价瑞格列奈片的生物等效性

目的 评价国产瑞格列奈片(规格:1.0 mg)的生物等效性并探索体内外相关性更好的溶出条件.方法 分别测定4个厂家制剂在5种溶出介质中的溶出曲线,采用GastroPlusTM软件建立瑞格列奈片的生理药动学模型,利用计算机技术模拟分析研究瑞格列奈片的体内外相关性,并基于不同厂家产品的体外溶出结果,利用Weibull函数,...