Absorption Systems uses the in situ perfused rat intestine model to evaluate intestinal permeability. In this model, an anesthetized rat is alive throughout the experiment, maintaining normal blood flow, innervation, etc. We expose the desired region of the intestine while leaving the mesentery intact, and cannulate a measured segment of intestine proximally and distally. Any region of the small or large intestine can be studied.
The rate of absorption (Peffective or Peff) is determined by measuring the concentration before and after incubation for a measured time interval. Using specific inhibitors, we can deduce the transporter(s) involved in uptake or efflux of a compound. We can also test the effects of excipients and compare different formulations.
Use of this Model:
Investigate whether a compound’s absorption is restricted to a specific segment of the GI tract.
Rank-order compounds in terms of intestinal permeability.
Determine the potential for transporter-based drug-drug interactions in the gut.
Identify the transporters involved in intestinal uptake and/or efflux.
Compare formulations and test the effects of individual excipients on drug permeation in different regions of the intestine.