Abstract
Theophylline (TN) loaded pellets containing 10% w/w drug were manufactured by extrusion/ spheronization technique in which; chitosan was blended in different concentrations with Avicel PH101 (R)-calcium phosphate (1:1) mixture. Mix torque rheometer was used to characterize pellets' wet mass in terms of the optimum binder ratio and mixing time. The results showed that the increasing chitosan weight ratio of the pellet wet mass caused increasing the wet mass consistency (peak torque) as well as increased the amount of binder (water) required for the formation of wet masses optimum for extrusion/ spheronization processes. Most of pellets wet masses exhibited 160 s as an optimum mixing time. Also, increasing chitosan level results in increasing pellet sizes. The results revealed that there was a correlation between pellet surface texture and their wet mass peak torque. Moreover, an inverse relationship was observed between TN dissolution rates from the pellets and the mean line torque of their wet masses.