Gastrointestinal transit monitoring and absorption of controlled-release pellets of diltiazem

The gastrointestinal (GI) transit and absorption of a multiparticulate controlled-release diltiazem formulation were investigated with reference to an innovator preparation. Transit of controlled-release pellets in GI tract was monitored using two marker drugs, namely paracetamol and sulfasalazine. Both formulations had little intersubject variation in gastric emptying and small intestine transit time. In both formulations, about 51% to 64% of the drug was absorbed while pellets were in the small intestine and the remaining amount while in the colon. The results found in this study were comparable to the other workers who used gamma scintigraphy or indirect method. Therefore, the method used in this study is a reliable alternative for studying GI transit of pellets.