Design and evaluation of sustained release bilayer tablets of propranolol hydrochloride CHINAM NIRANJAN PATRA* ARETHI BHARANI KUMAR HEMANT KUMAR PANDIT SATYA PRAKASH SINGH MEDURI VIMALA DEVI

used in the treatment of hypertension, angina pectoris, pheochromocytoma and cardiac arrhythmias (1). Because of its relatively short plasma half-life, patients are routinely asked to take propranolol hydrochloride in divided daily doses, once every 6 to 8 h. Such frequent drug administration may reduce patient compliance and therapeutic efficacy (2). In recent years, slow or sustained release formulations of propranolol hydrochloride have become available with claims that these formulations maintain beta adrenoreceptor blockade throughout a 24 h period and enable the drug to be given once daily (3). The multilayered tablet concept has been long utilized to develop sustained release formulations. Such a tablet has a fast releasing layer and may contain bior triple layers