Floating matrix dosage form for propranolol hydrochloride based on gas formation technique: development and in vitro evaluation.

Gastroretentive tablets of propranolol hydrochloride were developed by direct compression method using citric acid and sodium bicarbonate as the effervescent base. Hydroxypropyl methylcellulose; HPMC K15M was used to prepare the floating tablets to retard the drug release for 12h in stomach. Na-carboxymethyl cellulose (NaCMC) or carbopol 934P was added to alter the drug release profile or the dimensional stability of the formulation. Dicalcium phosphate (DCP) was used as filler. Formulations were evaluated for floating lag time, duration of floating, dimensional stability, drug content and in vitro drug release profile. The formulations were found to have floating lag time less than 1min. It was found that the dimensional stability of the formulations increase with increasing concentration of the swelling agent. The release mechanism of propranolol hydrochloride from floating tablets was evaluated on the basis of Peppas and Higuchi model. The ânâ value of the formulations ranged from 0.5201 to 0.7367 (0.5<n<1.0) which indicated anomalous (non-Fickian) transport mechanism. Formulation containing 27.5% HPMC K15M, 29% DCP, 3.75% citric acid and 18.75% sodium bicarbonate seemed most desirable. FTIR, DSC and XRPD studies indicated the absence of any significant chemical interaction within dug and excipients. Stability study of optimized formulation revealed no significant change and found to be stable.