Per-oral controlled release dosage form of theophylline using soybean protein

The potential of powdered soybean protein (SBP) as a vehicle for controlled drug release was investigated, using theophylline as the model drug, an in vitro dissolution test and in vivo absorption studies in beagle dogs. The results of the dissolution test demonstrated that the addition of SBP to the tablet brought about retarded dissolution of theophylline. In the in vivo absorption study, Tmax values for theophylline-SBP tablets were larger than those for tablets containing only theophylline; there was no difference in AUC between the two tablets. In addition, there was no detectable difference in the results with theophylline-SBP and Theodur tablets. The practical usefulness of SBP as a vehicle for controlled release tablets was confirmed not only from our in vitro experiment, but also from our in vivo absorption test using beagle dogs.