You might find these two projects helpful. They don't match the experiment you are doing, but both involve the way medicines move through the stomach and may help you think through the model you need:
Why Aren't All Medicines Pills?
https://www.sciencebuddies.org/science- ... alth/pills
Delayed Release Pill Challenge: Getting Medicine to the Right Place at the Right Time
https://www.sciencebuddies.org/science- ... -challenge
Amy
Science Buddies