Use of the BioDis to generate a physiologically relevant IVIVC

In the last decades there has been continual interest in site-specific delivery to the colon. Recently, new types of site-specific delivery formulations have been developed for the treatment of ulcerative colitis and other colon related diseases. The aim of the present study was to establish a physiologically relevant IVIVC for two prototypes using a prospective in vitro study. Caffeine, a drug being absorbed along the entire gastrointestinal tract, was selected as a model drug. USP apparatus 3, the BioDis, was used for all experiments and the passage through the gastrointestinal tract was simulated with a physiologically based pH-gradient. Subsequently, the fraction of drug released in vitro was compared with the fraction of drug released in vivo, which was determined in humans in a separate study. Results indicated that the BioDis method is very useful in terms of predicting the site/timing and extent of drug release from the prototypes, since an a priori IVIVC could be established. Moreover, from the results generated in the present study, it is obvious that novel pH- and time-based multi-unit formulations would improve selectivity of drug delivery to the distal ileum and the colon and therefore might be very helpful in the treatment of colonic diseases.