Study the effect of formulation variables on drug release from hydrophilic matrix tablets of milnacipran and prediction of in-vivo plasma profile

Abstract

The objective of this study was to design oral controlled release (CR) matrix tablets of Milnacipran using hydroxypropyl methylcellulose (HPMC) as the retardant polymer and to study the effect of various formulation factors such as polymer proportion, polymer viscosity, compression force and also the pH of dissolution medium on the in-vitro release of drug. Two viscosity grade of HPMC (15?K and 100?K) were used in the proportion of 50, 100, 150 and 200?mg per CR tablet. In-vitro release rate was characterized using various model dependent approaches and model independent dissolution parameters [T50% and T80% dissolution time, mean dissolution time (MDT), mean residence time (MRT), dissolution efficiency (DE)]. The statistical analysis was performed on all the model independent approaches using student t test and ANOVA. Results were found that as polymer concentration (50?mg to 200?mg) and viscosity (15?K to 100?K) increases, the MDT, MRT, T50% and T80% extended significantly. Drug release rate was found to be significantly different at different hardness. In-vivo human plasma concentration--time profile was predicted from in-vitro release data using convolution method. Predicted human pharmacokinetic parameters shows that the design CR formulation has capability to sustained the plasma drug level of milnacipran.     

酮洛芬羟丙基-β-环糊精分散片的处方研究和溶出度考察*

目的:制备酮洛芬羟丙基-β-环糊精包合物(KP-HP-β-CD)分散片并考察体外溶出度.方法:以崩解时间为指标,采用正交设计方法对处方进行筛选和优化,转篮法考察分散片的体外溶出度.结果:分散片优化处方的崩解剂为羧甲基淀粉钠(CMS-Na),用量12%,表面活性剂十二烷基硫酸钠(SLS)用量1%,分散片崩解时间为(112.7±5.0)s.体外溶出参数分别为:T50=3.0 min,Td=5.4 min.结论:该分散片符合中华人民共和国药典2005年版的规定,溶出速度明显快于普通片.     

Factors affecting drug release from hydroxypropyl methylcellulose matrix systems in the light of classical and percolation theories

Importance of the field: Hydroxypropyl methylcellulose (HPMC) is a versatile polymer widely used in the preparation of pharmaceutical dosage forms. The behavior of this polymer is a key factor in designing a variety of controlled release systems, especially hydrophilic matrices in which HPMC can be the only substance responsible for controlling the release rate of the drug.

Areas covered in this review: A new approach, proposed in 2004, based on percolation theory to explain the influence of the main formulation factors on drug release from HPMC matrices has been analyzed, paying attention to the advantages with respect to previous theories.

What the reader will gain: The influence of especially important factors such as polymer concentration and particle size is now much better known thanks to these new theories.

Take home message: To formulate a HPMC matrix, the system must be above the polymer's critical point, that is, allowing HPMC to act as outer phase. In this way, a coherent gel layer will be obtained because the first moment and the drug release will be controlled by this layer. Furthermore, knowing the critical points allows the vicinity of these points to be avoided, which are regions of high variability. In this way, robust dosage forms can be obtained.     

采用计算机模拟技术结合Caco-2细胞模型与溶出度试验考察国产盐酸曲美他嗪片的生物等效性

目的：采用计算机模拟技术结合Caco-2细胞模型和溶出度试验，对国产盐酸曲美他嗪生物等效性进行研究。方法：首先基于Caco-2单层细胞膜模型考察盐酸曲美他嗪的渗透性，获得其表观渗透系数P_app；第二步采用HPLC法测定溶出曲线来比较10家国产企业与原研生产的盐酸曲美他嗪片在5种不同pH条件下体外溶出行为的差异；最后采用Gastrol Plus^TM软件，导入本试验实测P_app，通过该软件转化为P_eff值，建立准确的体外溶出曲线与体内药动学曲线之间的相关性模型，基于该模型预测国产盐酸曲美他嗪片的药动学曲线，对其生物等效性进行体内外相关的研究。HPLC测定法：C₁₈柱，以0.287%无水庚烷磺酸钠-甲醇（55：45）为流动相，检测波长为231 nm，流速1.0 mL·min^-1；溶出度方法：分别以0.05 mol·L^-1盐酸溶液，pH 1.2、pH 4.0、pH 6.8缓冲盐溶液和水为溶出介质，桨法50 r·min^-1，溶出体积900 mL，分别考察片剂在上述5种溶出介质中5，10，5，20，30，45，60，90 min取样的溶出曲线。结果：盐酸曲美他嗪的表观渗透系数P_app值随着药物浓度的增加反而下降，属于中等渗透的药物；不同pH的溶出介质对盐酸曲美他嗪片的溶出行为无区分性；但在每种溶出介质中，国外原研片剂溶出较慢，与国产片剂的溶出行为存在明显差异，多数国产片剂快速溶出；采用Gastrol Plus^TM软件从药物在体内具有不同释放速率时的体内吸收情况与通过体外溶出曲线模拟体内吸收情况两个方面进行模拟研究，结果显示现有的国产盐酸曲美他嗪片与原研片剂在体内能够生物等效。结论：尽管国产盐酸曲美他嗪片的体外溶出曲线与原研片剂存在差别，但体内生物等效的可能性极大。Gastrol Plus^TM软件能够预测口服固体制剂与原研制剂的生物等效性，可在一致性评价工作中推广应用。     

药物溶出/吸收仿生系统研究丹酚酸B缓释片释放规律

目的：应用药物溶出/吸收仿生系统（drug dissolution/absorption simulating system,DDASS）研究丹酚酸B缓释片的体外释放规律,为中药活性成分缓控释制剂的设计提供新技术。方法：分别采用DDASS法和我国药典收载的桨法对丹酚酸B固体制剂进行体外释放度试验,高效液相色谱法定量,SPSS软件对累积释放度进行释放模型拟合。改进DDASS装置使研究对象从药物固体粉末或颗粒剂扩展到片剂、胶囊剂等多种剂型,分别评价丹酚酸B缓释片DDASS改进前、后和桨法中释放规律的相关性。结果：丹酚酸B原料药及其缓释片在改进前DDASS模型中释药过程符合Weibull方程;而丹酚酸B缓释片在改进后DDASS模型中释药过程符合一级动力学方程,与桨法评价结果一致。DDASS改进前、后与桨法释药规律相关性水平r值分别为0.7884（r5,0.05〈r前〈r5,0.001）和0.9982r后〉r5,0.001）。结论：丹酚酸B缓释片释药规律研究显示改进后DDASS法与桨法之间存在更为显著相关性。较之桨法,DDASS法模拟了一个连续动态的、更接近人体消化道环境的释药过程,表明该法评价药物固体制剂释药特性研究的合理性,为药物剂型设计研究提供了新的技术平台。     

Synchronized Release of Sulpiride and Sodium Decanoate from HPMC Matrices: A Rational Approach to Enhance Sulpiride Absorption in the Rat Intestine

Purpose. (a) To improve the absorption of sulpiride (SP) through the intestinal wall by incorporating it together with sodium decanoate (SD) into erodible matrices, designed to synchronize the release of SP and SD over different periods of time; (b) to test, in vivo the hypothesis that this simultaneous release increases SP absorption from the intestinal lumen. Methods. Matrix tablets, possessing different erosion rates, were prepared by changing the ratios between SD and hydroxypropyl methylcellulose (HPMC). The amounts of HPMC varied from 2.5% to 17% w/w. Double layer tablets, containing similar amounts of SP, SD, and HPMC were used as nonsynchronous controls. The erosion kinetics of the tablets was assessed gravimetrically in vitro in USP basket dissolution apparatus and in vivo in the intestine of the anesthetized rat after intra-intestinal administration. SP absorption was studied after intra-intestinal administration of the different kinds of tablets to anesthetized rats, by monitoring SP blood levels. SP and SD levels in the withdrawn samples from the dissolution systems and blood were analyzed by HPLC. Results. The controlled erosion of the tablets resulted in equal release rates of SP and SD during the initial linear phase of the process. This synchronized release lasted over different time periods depending on the relative amount of HPMC in the formulations (from 1 hour to 4 hours for 2.5 and 17 % w/w of HPMC, respectively). The synchronous matrices increased SP bioavailability after intra-intestinal administration. The increase varied from 1.4 to 2.3-fold for the slow and the fast release formulations, respectively (compared with the nonsynchronous, SD containing control formulations), indicating the ability to control both erosion rate and length of intestinal segment in which absorption is taking place. Conclusions. SP bioavailability after intestinal administration can be improved only if SP is released together with SD along the entire intestinal route. This can be accomplished by the design of synchronous matrices capable of concomitant release of SP and SD despite the differences in their water solubility. The ability to manipulate and control the duration of the synchronous phase of the matrices makes it possible for SP to be absorbed at different parts of the intestine.     

Improved in vitro dissolution parameters and in vivo hypolipidemic efficiency of atorvastatin calcium through the formation of hydrophilic inclusion complex with cyclodextrins

An aim of the present study was to improve the dissolution of the inherently low water solubility hypolipidemic agent, Atorvastatin calcium (ATC), through the preparation and characterization of ATC with cyclodextrins (CDs) inclusion complexes employing different techniques. A second goal was to study the in vivo hypolipidemic efficacy of ATC‐complexes with enhanced dissolution characteristics. Inclusion complexation of ATC with β‐cyclodextrin (β‐CD) and hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) was evaluated in aqueous and solid states. ATC formed inclusion complexes with β‐CD and HP‐β‐CD depending to a great extent upon ATC ionization state. Evaporation and freeze‐drying were the most efficient techniques to achieve complexation. In contrast, kneading was an inefficient tool to create true inclusion complexes, which could reflect the hindrance of drug–CDs interactions in the semisolid medium. The ATC:CD ratio of 1:2 showed better dissolution characteristics compared to a 1:1 ratio. Moreover, the in vivo hypolipidemic activities of ATC‐CDs (β‐CD and HP‐β‐CD) complexes were greater (P<0.05) than the other investigated formulations. Thus the nature of the carrier did not play a critical role in the dissolution characteristics of the inclusion system. In contrast, the carrier molar ratio, and the employed complexation technique were found to be key factors in enhancing the ATC dissolution rate, yielding performances as well as the in vivo hypolipidemic efficacies. Drug Dev Res 72: 379–390, 2011. © 2011 Wiley‐Liss, Inc.     

自微乳化技术与固体分散技术在改善长春西汀溶出度和生物利用度上的比较(英文)

探讨与比较自微乳化释药系统 (self-microemulsifying drug delivery systems, SMEDDS) 与固体分散体 (solid dispersion, SD) 在改善难溶性药物长春西汀 (vinpocetine, VIP) 溶出度和生物利用度方面的差异。本文选用中链甘油三酯 (Labrafac)、油酸、聚氧乙烯氢化蓖麻油 (Cremophor EL) 和二乙二醇单乙基醚 (Transcutol P) 为材料, 以微粉硅胶吸附制备长春西汀固体自微乳化释药系统 (VIP-SMEDDS); 采用泊洛沙姆188 (F68) 为载体制备长春西汀固体分散体 (VIP-SD)。溶解度实验结果表明, VIP在SMEDDS中的溶解度是SD载体中的17.3倍; 体外溶出度实验表明, VIP-SMEDDS的溶出效果和稳定性比VIP-SD更好; 大鼠体内生物利用度实验表明VIP-SMEDDS是VIP原料的1.89倍, 且不受食物影响, 而VIP-SD的生物利用度与VIP原料相比不具有显著性差异。给药2 h后组织分布结果表明, VIP-SMEDDS在Peyer’s节、肠道、肝脏的药物浓度分别是VIP-SD的3.7、2.2和1.5倍。Caco-2细胞转运实验表明VIP-SMEDDS的表观渗透系数 (P_app, cm·s⁻¹) 是VIP-SD的2.65倍。透射电镜下观察, VIP-SMEDDS组Caco-2细胞间隙是空白对照组的9.6倍, 而VIP-SD组与空白组比较无显著性差异。由此可见, 自微乳化技术在改善长春西汀溶解度、溶出度、肠黏膜透过率、淋巴吸收和生物利用度以及减少食物影响方面优于固体分散技术。     

往复筒法在药物溶出度研究中的应用进展

探讨往复筒溶出度测定方法的研究进展与应用现状。在查阅国内外往复筒法文献的基础上,对往复筒法的历史、发展历程、装置、工作原理、主要特点及其在药物制剂中的应用进行了回顾和阐述。往复筒法可以更好地满足复杂或新型制剂处方、工艺筛选及体外质量研究的需要,在药物制剂的研发与质量控制领域有着非常广阔的应用前景,对于开展体内外相关性研究也有重要的参考价值。     

Blends of hydrophobic and swelling agents in the swelling layer in the preparation of delayed-release pellets of a hydrophilic drug with low MW: Physicochemical characterizations and in-vivo evaluations

In this study, a hydrophobic material, ethylcellulose, which was used as its aqueous suspension Surelease^®, was combined with a swelling agent as the swelling layer to prepare delayed-release pellets for Danshensu, which is a hydrophilic drug with low MW. A rupturable, delayed-release pellet consists of a drug core, a swelling layer containing a swelling agent (cross-linked sodium carboxymethyl cellulose) with a hydrophobic agent (Surelease^®), and a controlled layer composed by an insoluble, water-permeable polymeric coating (aqueous ethylcellulose dispersions) was developed in a fluidised bed. Results showed that blending Surelease^® into the swelling layer could effectively extend the release of Danshensu from the pellets, which may be attributed to the slowed swelling rate by reduction of water penetration and improvement of mechanical integrity of the swelling layer. Drug in the delayed pellets showed sustained release in beagle dogs after oral administration with comparable in-vivo exposure to the uncoated drug pellets. In conclusion, blends of hydrophobic and swelling agents in the swelling layer in double-membrane pellets could achieve a delayed drug-release profile in vitro, as well as delayed and sustained absorption in vivo for highly soluble, low-MW drug. The present study highlighted the potential use of a delayed-release system for other hydrophilic, low-MW drugs to meet the formulation requirements for chronopharmacological diseases.