Formulation and in vitro evaluation of once-daily methyldopa sustained release matrix tablets

Methyldopa, an anti-hypertensive drug having a half life of less than 2 hours, and given with a dose of 250 mg 3-4 times daily. Objective: The present study was for objective of developing a sustained release (SR) matrix tablets of methyldopa using hydroxypropyl methylcellulose(HPMC) as release controlling factor, and to study the effect of some formulation factors on drug release from tablets. Methods: Hydrophilic SR matrix tablets containing 250 mg of methyldopa were prepared using wet granulation method. Granules were evaluated for moisture content, loose bulk density, tapped bulk density, compressibility index and hausner’s ratio. Tablets were subjected to physiochemical studies and in vitro dissolution study. Effect of concentration and viscosity grade of HPMC, both binder and lubricant concentration on drug release from matrix tablets was evaluated . Results: All formulations showed physiochemical properties which appear to be in compliance with pharmacopeial standards. From the in vitro dissolution studies, it was clear that as the concentration or viscosity of polymer increased, the rate of drug release was found to be decreased. Higher concentration of binder (PVP K30) showed slower release of drug, while the level of lubricant(magnesium stearate and talc) appeared to insignificantly affect release rates. Drug release kinetics of about all formulations correspond best to Korsemeyer-Peppas model and drug release mechanism was found to be anomalous (non-Fickian) diffusion based on release exponent value. The formulation F6 (containing 15% HPMC K100M ) was selected as the optimized formulation as it sustained the release over 24 hrs. Conclusion: The results of this study showed that the drug release from HPMC based matrix tablets using methyldopa as a drug model could be modulated by varying the polymer concentration, the polymer viscosity and the binder concentration with no significant effect of varying the lubricant concentration.

Formulation and evaluation of methyldopa sustained release matrix tablets

The objective of the present study was to formulate methyldopa sustained release matrix tablets using hydrophilic hydroxypropyl methylcellulose (HPMC) alone or in combination with hydrophobic ethyl cellulose polymer(EC). Matrix tablets were prepared by wet granulation method, and subjected to physiochemical studies. All formulations showed physiochemical properties which appear to be in compliance with pharmacopeial standards. The in-vitro dissolution studies showed that increase in concentration or viscosity of HPMC polymer led to decrease in the rate of drug release decreased. The results also revealed that Combination of HPMC K4M and EC slower drug release more than using HPMC K4M alone. Drug release kinetics of about all formulations correspond best to Korsemeyer-Peppas model and drug release mechanism was anomalous diffusion based on release exponent value.

The Influence of Type and Concentration of Polymer on Furosemide Release from Extended Hard Capsules

The aim of the present study is to prepare extended hard capsules of furosemide using Eudragit RL, Eudragit RS and Ethyl cellulose individually and in different ratios (6,8,12 and 15%). The granules were prepared by wet granulation using isopropyl alcohol as a granulating agent and then filled into capsules. The influence of different concentrations and type of polymer was studied. The prepared capsules assessed for their physicochemical properties and in-vitro drug release studies. In vitro release data show that Ethyl cellulose has more retardation than Eudragits, and Eudragit RS retards drug more than Eudragit RL does. Furthermore, higher concentration of polymer tends to more retardation than lower concentration.