DESIGN, DEVELOPMENT AND EVALUATION OF CARBAMAZEPINE BILAYERED TABLETS

Carbamazepine, also known as Tegretol, is an anticonvulsant drug and analgesic drug used to control seizures and to treat pain resulting from trigeminal neuralgia. It was initially approved by the FDA in 1965. Aside from the above uses, this drug is also given to control the symptoms of bipolar 1. Interestingly, carbamazepine was the first anticonvulsant used to treat individuals with bipolar disorder. The aim of present investigation is to increase the gastric residence time by preparing gastro retentive Bi-layered tablet thereby improving bioavailability. Maintaining constant blood levels of the drug in the bloodstream increases the therapeutic effectiveness of the drug. The present work aims to develop a stable and optimized bilayer dosage form containing immediate release and Extended-release. Best formulations of each layer were selected for bi-layered tablet and bi-layered tablet were prepared. Bi-layered tablet of Carbamazepine were subjected to hardness, weight variation, friability, drug content uniformity, in vitro drug release and drug polymer interaction. The above studies lid to following conclusions: Both immediate and sustained release layer were prepared by wet granulation method and punched separately. The prepared tablets of both layers were evaluated for post compression parameters. According to the in vitro dissolution profile date one formulation of each layer were selected for bi-layered tablet. IF6 from immediate release formulations as they showed 98.62 % drug release within 20 minutes. SF8 from sustained release formulation as they showed 94.29 % drug release within 18 hours. The bilayer tablets were prepared using the selected immediate and sustained release layer. The prepared tablets were found to be good and free from chipping and capping. The hardness of the prepared tablets was found to be in the range of 5.85 to 7.05 kg /cm2.The low values of the standard deviation of average weight of the prepared tablets indicate weight uniformity within the batches prepared. The friability of the prepared tablet was found to be less than 1%. The percentage drug content was uniform in all the formulations of prepared bi-layered tablets. In vitro drug release pattern of the bi-layered tablets were same as individual layer tablets. The stability study showed that no significant changes in tablets after 3 months study. Based on the observations, it can be concluded that the formulated bi-layered tablets of Carbamazepine using super disintegrants, release retardant polymers and different excipients was capable of exhibiting all the properties of bi-layered tablet. They are thus reducing the dose intake, minimize dose related adverse effect, cost and ultimately improve the patient compliance and drug efficiency.