ORAL SUSTAINED RELEASE PELLETS OF DILTIAZEM HCL WITH KOLLICOAT SR30

An aqueous dispersion of polyvinyl acetate (Kollicoat SR30) was selected for the development and in vitro evaluation of diltiazem sustained release pellets. Five coating levels based on theoretical weight gains of 7, 8, 9, 10 and 11% were examined onto drug pellets using fluidized bed technique. Coated pellets were thermally treated at 37°C, 40°C, 50°C and 60°C for 24 hours. In vitro dissolution tests were performed in distilled water while selected batches were compared to the release data in test media having pH 1, 4 and 7. The release profiles of coated pellets were found to be inversely proportional to the thickness of Kollicoat SR30 coat and desirable controlled release characteristics could be achieved by manipulating the coating levels. Plasticizers (propylene glycol/triethyl citrate) and anti-adherent (magnesium stearate) in the formulation of coated pellets reduced the release rates. Thermally treated pellets also showed reduction in the release rates at 60°C compared to initial release profile at 37°C. However, the drug release rates was found to be fairly independent of dissolution media (pH 1,4 and 7).