Measurement of theophylline absorption from different regions of the gastro-intestinal tract using a remote controlled drug delivery device.

The absorption of a theophylline solution containing 80-120 mg doses delivered to different sites in the gastro-intestinal tract has been determined in 3 male volunteers using a remote controlled drug release system (HF-capsule). There was no difference between the stomach, ileum and the colon in the amount of theophylline absorbed (AUC). The T 1/2abs of theophylline absorbed via the colon was prolonged when compared with that entering via the upper gastro-intestinal tract. The results provide a rational basis for the further development of theophylline formulations and are indispensable for planned development and to account for variation in the bioavailability of retarded release drug preparations.