Sustained release characteristics of pellets and compressed pellets containing lipidic or waxy substances

Abstract

Propranolol HCl wax matrix pellets were prepared by extrusion-spheronization technique. Various kinds of waxy material were used as matrix forming agent. Lactose was chosen as channeling agent in the formulation. The type and amount of matrix additives affected the condition of extrusion-spheronization process and the physical properties of matrix pellets. The release characteristics of propranolol HCl form wax matrix pellet were not prolonged enough to have sustained release properties as required except those containing highest percent percent of Compritol. Thus, compaction of matrix pellets in to matrix tablet was very effective way for reducing drug release rate as required. The release rate was decreased with an increase in the content of wax or propranolol HCl, whereas increasing lactose tended to increase the drug release. The release characteristics of propranolol HCl from all from all formulations depended on environmental pH medium. Lubritab, Compritol, and Precirol were found to be the most suitable waxes during the production process and exhibited the most satisfactory release profiles. Adjusting the level of these waxes or other additives could provide the release of propranolol HCl matrix tablet in compliance with commercial products. The IR spectra of the obtained matrices indicated no interaction between drug, wax, and other additives in the formulation. Propranolol HCl was still in crystalline form and characteristic peaks of propranolol HCl were observed and negligibly shifted by x-ray diffractometry investigation. The position of the major peaks remained relatively unchanged by DSC investigation.