Development and in Vitro Evaluation of Once Daily Carbamazepine Matrix Tablet from Hydrophilic Polymers

The purpose of study was to develop and characterize once daily extended release matrix tablets of Carbamazepine (CBZ), an antiepileptic drug. Tablets were prepared by wet granulation method. Methocel K15M CR and Methocel K100LV CR polymers were used as rate retarding agents in fourteen formulations. The granules were evaluated for angle of repose, loose bulk density, tapped bulk density, compressibility index, total porosity, drug content etc. and showed satisfactory results. The tablets were subjected to thickness, weight variation test, drug content, hardness, friability and in vitro release studies. All the tablet formulations showed acceptable pharmacotechnical properties and complied with pharmacopoeial specifications for tested parameters. The in vitro dissolution study was carried out for 24 hour in distilled water as the dissolution medium. The release mechanisms were explored and explained by Zero order, Higuchi, First order, Korsmeyer-Peppas and Hixson-Crowell equations. Primarily nine formulations were prepared by using three variable ratios of the two polymers, with 1% sodium lauryl sulphate. The optimized formulations F-5, F6 and F-9 were further studied to know the effect of solubilizer on release by using various concentration of sodium lauryl sulphate and glyceryl mono stearate. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism followed anomalous type or non-Fickian transport and super case II transport. The release of drug was extended for 24 hour by polymer combinations which indicated the usefulness of the formulations for once daily dosage form. Besides, these studies explored both of the optimum concentration, effect of polymers and the use of sodium lauryl sulphate on CBZ release pattern from the tablet matrix for 24 hour period. INTRODUCTION: CBZ is an antiepileptic drug and also used to treat trigeminal neuralgia. CBZ blocks sodium channel at therapeutic concentrations and inhibits highfrequency repetitive firing in neuron in culture. It also acts presynaptically to decrease synaptic transmission. These effects probably account for the anticonvulsant action of CBZ. The successful formulation to control drug for the required duration of time with optimum release mode depends on various factors, such as the physicochemical properties of the drug, the nature of drug-carrier matrix, the type of the dosage form and the route of administration . To reduce the frequency of administration and to improve patient compliance, a once-daily extendedrelease formulation of CBZ is desirable .