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Development and in vitro Evaluation of Sustained Release Matrix Tablet formulatios of Metoprolol Tartrate

Ramesh V. Shinde, Dattatreya B. Udgirkar and K. Sreenivasa Rao

In the present study, metoprolol tartrate (MT) was chosen as a model drug, which is a -1- selective adrenergic blocking agent and is prescribed widely in diverse cardiovascular diseases like hypertension; angina pectoris, arrhythmias and myocardial infarction but because of its short half life (3-4 hrs) and its high water solubility, it was chosen as a suitable candidate for sustained release matrix tablet formulation. It was formulated into matrix tablet using hydrophilic polymers such as hydroxy propyl methyl cellulose (HPMC 15 cps), sodium carboxy methyl cellulose (NaCMC) and guar gum (GG) as release retardants. All the precompressional parameters like angle of repose, Hausner’s ratio and Carr’s index were found to be within the standard limits. Tablets were evaluated for hardness, friability, thickness, drug content, in vitro release, swelling and stability study. The effect of polymer concentration, binary polymer mixture and wet granulation methods on drug release profiles was studied. It was observed that the type of polymer and its concentration has influenced the drug release from matrix tablets. Matrix tablets that contained a blend of HPMC and sodium carboxy methyl cellulose successfully sustained the release of metoprolol tartrate for a period of 12 hrs. Precompressional parameters indicated that granules used for preparing tablets were free flowing. Postcompressional parameter like hardness, friability, thickness and drug content were within the acceptable limits. The concentration of metoprolol tartrate was kept constant (100 mg) Formulation containing only a single polymer could not control the release of metoprolol tartrate. The sustained release from sodium carboxy methyl cellulose and hydroxy propyl methyl cellulose combination was due to interaction between ionic polymer and non-ionic polymer, which resulted in favorable increase in the water uptake capacity and gel viscosity leading to a better control over the release of metoprolol tartrate. HC1 and HC2 showed the sustained release of metoprolol tartrate as desired. Model fitting data showed good correlation coefficient with Higuchi’s kinetics. The study revealed that the combination of NaCMC and HPMC can be used for the formulation of sustained release matrix tablets of metoprolol tartrate.