星点设计-效应面法优化盐酸苯环壬酯控释片的处方

目的：采用星点设计-效应面法优化盐酸苯环壬酯控释片处方,制备盐酸苯环壬酯控释片并考察其稳定性。方法：根据单因素实验结果,选择含药层氯化钠含量、助推层高取代聚氧乙烯（WSR-HM）含量和包衣增重为自变量,以12 h累积释放度和药物释放曲线拟合度为因变量,应用星点设计-效应面法筛选最佳处方并验证。结果：Quadratic多项式模型为最佳拟合模型,盐酸苯环壬酯控释片的最优处方为：含药层氯化钠含量为5 mg/片,助推层高取代聚氧乙烯含量为47.5 mg/片,包衣增重为14%。优化制得的3批样品12 h平均累积释放度分别为99.89%、98.66%、99.36%,释药曲线线性拟合度R²分别为0.897 1、0.921 0、0.931 9,实测值与预测值无显著差异。稳定性试验表明,该制剂稳定性良好。结论：采用星点设计-效应面法筛选得到的优化处方合理,制得的盐酸苯环壬酯控释片具有显著缓释作用。     

星点设计-效应面法优化尼美舒利双层渗透泵片处方

目的制备大剂量难溶性药物尼美舒利双层渗透泵片,并考察其处方因素和体外释放行为,优化尼美舒利双层渗透泵的处方。方法以12 h药物累积释放量、释放曲线的线性为考察指标,以含药层聚氧乙烯量、包衣膜中致孔剂量、包衣增质量,为考察的主要因素,采用星点设计-效应面法对尼美舒利渗透泵片处方进行优化,并对优化处方进行验证。结果成功找到了最优释药区域,优化处方为:含药层聚氧乙烯220.27 mg,致孔剂用量质量分数为19.27%,包衣增质量6.81%。自制渗透泵与预测值基本一致,2~12 h内药物呈零级释放特征。结论星点设计-效应面法成功建立了处方优化模型,实现了尼美舒利双层渗透泵的处方筛选。     

Design,Development and Optimization of S (-) Atenolol Floating Sustained Release Matrix Tablets Using Surface Response Methodology

The objective of this present investigation was to develop and formulate floating sustained release matrix tablets of s (-) atenolol, by using different polymer combinations and filler, to optimize by using surface response methodology for different drug release variables and to evaluate the drug release pattern of the optimized product. Floating sustained release matrix tablets of various combinations were prepared with cellulose-based polymers: Hydroxypropyl methylcellulose, sodium bicarbonate as a gas generating agent, polyvinyl pyrrolidone as a binder and lactose monohydrate as filler. The 3² full factorial design was employed to investigate the effect of formulation variables on different properties of tablets applicable to floating lag time, buoyancy time, % drug release in 1 and 6 h (D_{1 h,}D_{6 h}) and time required to 90% drug release (t_90%). Significance of result was analyzed using analysis of non variance and P < 0.05 was considered statistically significant. S (-) atenolol floating sustained release matrix tablets followed the Higuchi drug release kinetics that indicates the release of drug follows anomalous (non-Fickian) diffusion mechanism. The developed floating sustained release matrix tablet of improved efficacy can perform therapeutically better than a conventional tablet.     

Optimization of drug release from compressed multi unit particle system (MUPS) using generalized regression neural network (GRNN)

The purpose of this study was development of diclofenac sodium extended release compressed matrix pellets and optimization using Generalized Regression Neural Network (GRNN). According to Central Composite Design (CCD), ten formulations of diclofenac sodium matrix tablets were prepared. Extended release of diclofenac sodium was acomplished using Carbopol® 71G as matrix substance. The process of direct pelletisation and subsequently compression of the pellets into MUPS tablets was applied in order to investigate a different approach in formulation of matrix systems and to achieve more control of the process factors over the principal response — the release of the drug. The investigated factors were X₁ -the percentage of polymer Carbopol® 71 G and X₂- crushing strength of the MUPS tablet. In vitro dissolution time profiles at 5 different sampling times were chosen as responses. Results of drug release studies indicate that drug release rates vary between different formulations, with a range of 1 hour to 8 hours of dissolution. The most important impact on the drug release has factor X₁ -the percentage of polymer Carbopol® 71 G. The purpose of the applied GRNN was to model the effects of these two causal factors on the in vitro release profile of the diclofenac sodium from compressed matrix pellets. The aim of the study was to optimize drug release in manner wich enables following in vitro release of diclofenac sodium during 8 hours in phosphate buffer: 1 h: 15–40%, 2 h: 25–60%, 4 h: 35–75%, 8 h: >70%.     

Preparation and in vitro evaluation of sustained release tablet formulations of diclofenac sodium

The effects of formulation variables on the release profile of diclofenac sodium (DS) from hydroxypropylmethyl cellulose (HPMC) and chitosan matrix tablets were studied. DS tablets were prepared by wet granulation and direct compression methods and different ratios of HPMC and chitosan were used. Physical properties of the prepared tablets and targeted commercial sustained release (SR) tablet and the drug release were studied in tablets that were placed in 0.1 M HCl for 1 h and phosphate buffer solution was added to reach pH value of 7.5. In vitro studies showed that 20% HPMC contained SR formulation with direct (dry) compression method is the optimum formulation due to its better targeting profile in terms of release. This formulation also exhibited the best-fitted formulation into the zero order kinetics. The precision and accuracy of the analytical method were also checked. The repeatability and reproducibility of the method were also determined.     

Duel-Acting Subcutaneous Microemulsion Formulation for Improved Migraine Treatment with Zolmitriptan and Diclofenac: Formulation and In Vitro-In Vivo Characterization

Subcutaneous triptan provides immediate analgesia in migraine and cluster headache but is limited by high pain recurrence due to rapid drug elimination. A dual-acting subcutaneous formulation providing immediate release of a triptan and slow but sustained release of a nonsteroidal anti-inflammatory drug may provide a longer duration of relief. A microemulsion-based technology has various advantages over other technically complex dosage forms. Oil-in-water microemulsions of zolmitriptan and diclofenac acid using Labrafac Lipophile, Tween 80, Capryol 90 and water were prepared. One formulation was characterised in vitro and found to have uniformly dispersed nanosized globules. The formulation provided differential release of zolmitriptan and diclofenac acid both in vitro as well as in vivo that may be potentially beneficial to migraine patients.     

Development and evaluation of natural gum-based extended release matrix tablets of two model drugs of different water solubilities by direct compression

The study was aimed at developing extended release matrix tablets of poorly water-soluble diclofenac sodium and highly water-soluble metformin hydrochloride by direct compression using cashew gum, xanthan gum and hydroxypropylmethylcellulose (HPMC) as release retardants. The suitability of light grade cashew gum as a direct compression excipient was studied using the SeDeM Diagram Expert System. Thirteen tablet formulations of diclofenac sodium (∼100 mg) and metformin hydrochloride (∼200 mg) were prepared with varying amounts of cashew gum, xanthan gum and HPMC by direct compression. The flow properties of blended powders and the uniformity of weight, crushing strength, friability, swelling index and drug content of compressed tablets were determined. In vitro drug release studies of the matrix tablets were conducted in phosphate buffer (diclofenac: pH 7.4; metformin: pH 6.8) and the kinetics of drug release was determined by fitting the release data to five kinetic models. Cashew gum was found to be suitable for direct compression, having a good compressibility index (ICG) value of 5.173. The diclofenac and metformin matrix tablets produced generally possessed fairly good physical properties. Tablet swelling and drug release in aqueous medium were dependent on the type and amount of release retarding polymer and the solubility of drug used. Extended release of diclofenac (∼24 h) and metformin (∼8–12 h) from the matrix tablets in aqueous medium was achieved using various blends of the polymers. Drug release from diclofenac tablets fitted zero order, first order or Higuchi model while release from metformin tablets followed Higuchi or Hixson-Crowell model. The mechanism of release of the two drugs was mostly through Fickian diffusion and anomalous non-Fickian diffusion. The study has demonstrated the potential of blended hydrophilic polymers in the design and optimization of extended release matrix tablets for soluble and poorly soluble drugs by direct compression.     

Effect of formulation variables on in vitro release of a water-soluble drug from chitosan–sodium alginate matrix tablets

The objective of this study is to investigate the feasibility of using chitosan–sodium alginate (CS–SA) based matrix tablets for extended-release of highly water-soluble drugs by changing formulation variables. Using trimetazidine hydrochloride (TH) as a water-soluble model drug, influence of dissolution medium, the amount of CS–SA, the CS:SA ratio, the type of SA, the type and amount of diluents, on in vitro drug release from CS–SA based matrix tablets were studied. Drug release kinetics and release mechanisms were elucidated. In vitro release experiments were conducted in simulated gastric fluid (SGF) followed by simulated intestinal fluid (SIF). Drug release rate decreased with the increase of CS–SA amount. CS:SA ratio had only slight effect on drug release and no influence of SA type on drug release was found. On the other hand, a large amount of water-soluble diluents could modify drug release profiles. It was found that drug release kinetics showed the best fit to Higuchi equation with Fickian diffusion as the main release mechanism. In conclusion, this study demonstrated that it is possible to design extended-release tablets of water-soluble drugs using CS–SA as the matrix by optimizing formulation components, and provide better understanding about drug release from CS–SA matrix tablets.     

Effect of drug release rate on therapeutic outcomes: formulation dependence of gastrointestinal toxicity of diclofenac in the rat

- The use of the non-steroidal anti-inflammatory drug, diclofenac, is associated with occasional serious side effects in the gastrointestinal (GI) tract. We examined the effect of altering the site of release of diclofenac sodium on GI tract side effects. Dissolution and pharmacokinetic studies were carried out to substantiate the sustained-release nature of crushed sustained release tablet. Adult male Sprague–Dawley rats were administered diclofenac 10 mg/kg orally as either immediate-release or sustained-release preparations. Upper and lower GI permeability, as a surrogate marker of toxicity, were measured using sucrose and ⁵¹Cr-EDTA, respectively. Immediate- and sustained-release preparations similarly increased upper GI permeability. The induced toxicity in the lower GI tract, however, caused by the sustained-release formulation lasted longer than that of the immediate release formulation. Since both immediate- and sustained-release preparations of diclofenac increased sucrose permeability, the upper GI damage caused by diclofenac may be attributable mainly to a systemic mechanism. The prolonged lower GI toxicity following the sustained-release preparation may be related to a greater residence time therein.     

氨酚氯雷伪麻缓释片的制备及其体外释放度的研究

目的研制亲水凝胶骨架型氨酚氯雷伪麻缓释片,并考察其体外释放度。方法采用湿法制粒工艺,以羟丙基甲基纤维素(HPMC)为缓释骨架材料,制备了氨酚氯雷伪麻缓释片。以对乙酰氨基酚的体外释放度为考察指标,通过正交试验筛选出最佳处方,并考察了原料药粒径、HPMC和碳酸氢钙的用量、颗粒水分和制片压力对缓释片中对乙酰氨基酚体外释放速率的影响。结果原料药粒径、HPMC用量、颗粒水分和制片压力对氨酚氯雷伪麻缓释片体外释放速率有明显的影响;碳酸钙用量对释放速率基本无影响。结论按优化处方制备的氨酚氯雷伪麻缓释片缓释效果明显,符合相关规定,可应用于工业化大生产。     

Formulation Design and Optimization of Orodispersible Tablets of Quetiapine Fumarate by Sublimation Method

The objective of present study was to formulate directly compressible orodispersible tablets of quetiapine fumarate by sublimation method with a view to enhance patient compliance. A full 3² factorial design was used to investigate the effect of two variables viz., concentration of Indion 414 and camphor. Indion 414 (3-5 % w/w) was used as superdisintegrant and camphor (5-15 % w/w) as subliming agent. The tablets were evaluated for thickness, weight variation, hardness, friability, content uniformity, wetting time, porosity, in vitro disintegration time and in vitro drug release. The formulation containing 5% w/w of Indion 414 and 5% w/w camphor was emerged as promising based on evaluation parameters. The disintegration time for optimized formulation was 18.66 s. The tablet surface was evaluated for presence of pores by scanning electron microscopy before and after sublimation. Differential scanning colorimetric study did not indicate any drug excipient incompatibility, either during mixing or after compression. The effect of independent variables on disintegration time, % drug release and friability is presented graphically by surface response plots. Short-term stability studies on the optimized formulation indicated no significant changes in drug content and in vitro disintegration time. The directly compressible orodispersible tablets of quetiapine fumarate with lower friability, greater drug release and shorter disintegration times were obtained using Indion 414 and camphor at optimum concentrations.     

Modulation of Venlafaxine Hydrochloride Release from Press Coated Matrix Tablet

The aim of present study was to prepare novel modified release press coated tablets of venlafaxine hydrochloride. Hydroxypropylmethylcellulose K4M and hydroxypropylmethylcellulose K100M were used as release modifier in core and coat, respectively. A 3² full factorial design was adopted in the optimization study. The drug to polymer ratio in core and coat were chosen as independent variables. The drug release in the first hour and drug release rate between 1 and 12 h were chosen as dependent variables. The tablets were characterized for dimension analysis, crushing strength, friability and in vitro drug release. A check point batch, containing 1:2.6 and 1:5.4 drug to polymer in core and coat respectively, was prepared. The tablets of check point batch were subjected to in vitro drug release in dissolution media with pH 5, 7.2 and distilled water. The kinetics of drug release was best explained by Korsmeyer and Peppas model (anomalous non-Fickian diffusion). The systematic formulation approach enabled us to develop modified release venlafaxine hydrochloride tablets.     

Formulation and In vitro assessment of sustained release terbutaline sulfate tablet made from binary hydrophilic polymer mixtures

In the present systematic study, a sustained release of terbutaline sulfate tablet (TBS) was developed and optimized by employing the hydrophilic polymers; chitosan and xanthan gum mixed with sodium bicarbonate as a release modifying agent. This formulation was developed using direct compression technology. In vitro release studies indicated rapid swelling and drug release in the initial period of the acid stage from a matrix composed of chitosan and xanthan gum solely. Addition of sodium bicarbonate to the matrix resulted in sustained drug release. Various formulation factors such as polymer to polymer ratio, polymer viscosity and particle size were altered and their effect on dissolution pattern was illustrated. Manufacturing variables such as compression force and lubricant percentage were investigated and found not to influence the drug release profile of the resulted tablets. The release mechanism follows Korsmeyer-Peppas equation with n value indicating non-Fickian diffusion. The release profiles were analyzed using statistical method (one-way ANOVA) and f₂ metric values and found to be similar to the commercial product Bricanyl^®. Reproducible data were obtained when scale-up of the formulation was performed.     

Microporous bilayer osmotic tablet for colon-specific delivery

Microporous bilayer osmotic tablet bearing dicyclomine hydrochloride and diclofenac potassium was developed using a new oral drug delivery system for colon targeting. The tablets were coated with microporous semipermeable membrane and enteric polymer using conventional pan-coating process. The developed microporous bilayer osmotic pump tablet (OPT) did not require laser drilling to form the drug delivery orifice. The colon-specific biodegradation of pectin could form in situ delivery pores for drug release. The effect of formulation variables like inclusion of osmogen, amount of HPMC and NaCMC in core, amount of pore former in semipermeable membrane was studied. Scanning electron microscopic photographs showed formation of in situ delivery pores after predetermined time of coming in contact with dissolution medium. The number of pores was dependent on the amount of the pore former in the semipermeable membrane. In vitro dissolution results indicated that system showed acid-resistant, timed release and was able to deliver drug at an approximate zero order up to 24 h. The developed tablets could be effectively used for colon-specific drug delivery to treat IBS.     

Microwave assisted synthesis and evaluation of modified pea starch as tablet superdisintegrant

In the present study, cross linked sodium carboxymethylated pea starch (SCPS) was synthesized and evaluated as tablet superdisintegrant in diclofenac sodium based tablets. SCPS was synthesized using native pea starch with monochloroacetic acid and NaOH in microwave radiation environment. Finally the dried product was cross-linked with phosphorous oxychloride, which produced granular highly swellable starch. SCPS with degree of substitution of 0.34 was formed and it was further evaluated as superdisintegrant in diclofenac sodium based tablets. Diclofenac sodium tablets were prepared by direct compression method with 2, 4, 6 and 8%w/w of SCPS as superdisintegrant and further comparatively evaluated for in vitro disintegration and dissolution study with Sodium starch glycolate containing tablets as reference. The results revealed that SCPS could be a promising superdisintegrant for immediate release tablets in concentration dependant manner.     

双氯芬酸赖氨酸盐缓释片的制备及体外释放度

目的：制备双氯芬酸赖氨酸盐缓释片,对其释放机制进行考察。方法：以羟丙基甲基纤维素（HPMCK4M）为主要辅料,制备水溶性骨架片,通过正交设计优化出双氯芬酸赖氨酸盐缓释片的处方,以进口双氯芬酸钠缓释片为对照,根据中国药典1995年版所载的溶出方法测定其释放度。结果：所制备的缓释片在12;h内呈现良好的零级释药特征。结论：以正交法优选的双氯芬酸赖氨酸盐缓释片处方合理,体外释放与进口双氯芬酸钠缓释片相比差异无显著性。     

Development of enzyme-controlled colonic drug delivery using amylose and hydroxypropyl methylcellulose: optimization by factorial design

The aim of the present study is to develop colon-targeted drug delivery systems for diclofenac sodium which release the drug specifically and instantly at target site using amylose as a carrier. Coating formulations were designed based on the full factorial design. The evaluated responses were lag time prior to drug release and T90. Compression-coated tablets of diclofenac sodium containing various proportions of amylose and HPMC were prepared. In vitro drug release studies were done by changing pH method with enzyme. In vivo studies were done to confirm the potential of formulation to release the drug at target site. The dissolution data revealed that the ratio of polymers is very important to achieve optimum formulation. Results showed that the tablet prepared according to the above formulation released drug instantly at pH 6.8 (simulating colonic pH). An in vivo study shows that optimized formulation disintegrated in the target region. The results of this study revealed that factorial design is a suitable tool for optimization of coating formulations to achieve colon delivery. It was shown that coating formulation consisting of amylose 285 mg and HPMC 150 mg coating has the potential for colonic delivery of diclofenac sodium irrespective of change in pH in a patient with IBD.     

Formulation development and optimization of bilayer tablets of aceclofenac

Objective: The objective of the present study was to develop bilayer tablets of aceclofenac that are characterized by initial burst drug release followed by sustained release of drug.

Methods: The fast-release layer of the bilayer tablet was formulated using microcrystaline cellulose (MCC) and HPMC K4M. The amount of HPMC E4M (X₁) and MCC (X₂) was used as independent variables for optimization of sustained release formulation applying 3² factorial design. Three dependent variables were considered: percentage of aceclofenac release at 1 h, percentage of aceclofenac release at 12 h, and time to release 50% of drug (t_50%). The composition of optimum formulation of sustained release tablets were employed to formulate double layer tablets.

Results: The results indicate that X₁ and X₂ significantly affected the release properties of aceclofenac from sustained release formulation. The double layer tablets containing fast-release layer showed an initial burst drug release of more than 30% of its drug content during first 1 h followed by sustained release of the drug for a period of 24 h.

Conclusion: The double layer tablets for aceclofenac can be successfully employed as once-a-day oral-controlled release drug delivery system characterized by initial burst release of aceclofenac for providing the loading dose of drug.     

Controlled release reservoir mini tablets approach for controlling the drug release of Galantamine Hydrobromide

The objective of this study is to explore and investigate the reservoir mini tablets approach to control the release of Galantamine Hydrobromide in comparison to desired release profile to the Innovator formulation Razadyne^® ER capsules as disclosed in US Patent 7,160,559 which is granted to Janseen Pharmaceutica NV. The core mini tablets were prepared using the direct compression and wet granulation methods. These core mini tablets were further coated with Galantamine Hydrobromide in two different portions; 70% as controlled release and 30% as immediate release and then filled in empty hard gelatin capsule shells. The dissolution profiles of each formulation were compared to those of Razadyne^® ER capsules and the mean dissolution time (MDT), dissolution efficiency (DE%) and dissolution similarity (f2 factor) were calculated. It was observed that core formulation plays an important role in controlling the drug release as well as maintaining pH independent drug release profile. The release mechanism of GAH from reservoir mini tablet formulation follows Higuchi and first order. These results imply that controlled release reservoir mini tablets which further filled into empty hard gelatin capsule shells can be a suitable method to formulate controlled release Galantamine hydrobromide.     

Enhanced bioavailability of buspirone hydrochloride via cup and core buccal tablets: Formulation and in vitro/in vivo evaluation

This work aims to prepare sustained release buccal mucoadhesive tablets of buspirone hydrochloride (BH) to improve its systemic bioavailability. The tablets were prepared according to 5 × 3 factorial design where polymer type was set at five levels (carbopol, hydroxypropyl methylcellulose, sodium alginate, sodium carboxymethyl cellulose and guar gum), and polymer to drug ratio at three levels (1:1, 2:1 and 3:1). Mucoadhesion force, ex vivo mucoadhesion time, percent BH released after 8 h (Q8h) and time for release of 50% BH (T_50%) were chosen as dependent variables. Additional BH cup and core buccal tablets were prepared to optimize BH release profile and make it uni-directional along with the tablets mucoadhesion. Tablets were evaluated in terms of content uniformity, weight variation, thickness, diameter, hardness, friability, swelling index, surface pH, mucoadhesion strength and time and in vitro release. Cup and core formula (CA10) was able to adhere to the buccal mucosa for 8 h, showed the highest Q8h (97.91%) and exhibited a zero order drug release profile. Pharmacokinetic study of formula CA10 in human volunteers revealed a 5.6 fold increase in BH bioavailability compared to the oral commercial Buspar^® tablets. Conducting level A in vitro/in vivo correlation showed good correlation (r² = 0.9805) between fractions dissolved in vitro and fractions absorbed in vivo.