Development and evaluation of elementary osmotic pump of highly water soluble drug: tramadol hydrochloride.

In the present study Elementary osmotic pump (EOP) of highly water soluble drug tramadol hydrochloride (TRH) was developed and evaluated. Target release profile was selected and different variables were optimized to achieve the same. Formulation variables like levels of swellable polymer (10-21.87%) and plasticizer (0-20% w/w of polymer), and coat thickness of semipermeable membrane (SPM) were found to affect the drug release from the developed formulations. TRH release was directly proportional to the level of plasticizer and osmotic pressure generated by osmotic agent but inversely proportional to the level of swellable polymer within the core and coat thickness of SPM. Drug release from developed formulations was independent of pH and agitation intensities of release media. Burst strength of the exhausted shells increased with increase in coat thickness but decreased with increase in level of plasticizer. The in-vitro results of the developed formulations were compared with performance of standard marketed formulation of TRH. The developed formulation provided more prolonged and controlled TRH release as compared to marketed formulation. The manufacturing procedure was found to be stable during six months of accelerated stability study.