Original Articles
Kamble Ravindra K., Chetan S C
Abstract
The present research was aimed to design controlled release ion exchange resinates of BCS class I drug Tramadol hydrochloride (TH) a centrally acting synthetic analgesic. Complexes of ion-exchange resins and tramadol hydrochloride, a model drug, were prepared using different methods including a single batch and modified method with different functional groups, ion-exchange capacity, degree of crosslinking, and resin particle size. Drug loading efficiency, release profiles were investigated. Most of the functional groups of resins were loaded with tramadol hydrochloride after the completion of a double batch method and it was recommended for drug loading into the ion-exchange resin. Tramadol hydrochloride could be loaded onto resin, depending on the physicochemical properties of the resin. As the crosslinking ratio and particle size increased, the drug loading and release rate decreased due to the reduced effective diffusion coefficient and surface area. In vitro drug release profiles of resinate shown the pH independent release. Also the ionic strength and valency of dissolution medium has influence on drug release. Assuming that the resin particles are uniform spheres of radius r, release mechanism was evaluated using plots of a Bt−t relationship, where B and t are the rate constant and time, respectively. The Bt−t plots displayed a straight line indicating that the diffusion of tramadol hydrochloride in the resin matrix is the rate-controlling step. Tramadol hydrochloride resinates in vitro drug release shown significant sustained release up to 6 hours.