| Dextromethorphan hydrobromide (DM) sustained release matrix pellets containing 10% w/w drug were prepared by an extrusion/spheronization technique. The effect of mixing different concentrations of ethyl cellulose (EC), hydroxypropyl methylcellulpse (HPMC K10), and Carbopol 934 with Avicel PH101 on the rheological properties of pellet wet mass was evaluated using mixer torque rheometry (MTR). The prepared pellets were characterized for size, drug content, and in-vitro DM release rate. The results showed that increasing the concentration of the hydrophobic polymer (EC) with Avicel PH101 decreased wet mass consistency, represented by mass mean line torque. Lower binder ratio was required for optimum wet massing, while mixing with swellable polymers (HPMC and... |
