Testing Coated Aspirin at Home

Q. I take 81 mg enteric-coated aspirin daily to protect my heart. I put one of the tablets in a vase to keep some cut flowers fresh and noticed that in two days the coated aspirin did not dissolve. Does this indicate that the aspirin is not being absorbed into my body?
A. Enteric coatings are designed to release the ingredients of a pill into the small intestine so they are less likely to irritate the stomach. Factors that affect this process include pH and salts.
To answer your question, we consulted Dr. Robin Bogner, Associate Professor of Pharmacy at the University of Connecticut. She noted that acidity in the stomach prevents the pills from dissolving. The intestine, however, is more basic and contains salts (ions) that facilitate breakdown of the enteric coating.
Tap water in a vase could be slightly acidic and contains few ions, which is probably why the aspirin didn’t dissolve. You may wish to repeat your test by putting an aspirin in a dilute baking soda solution and adding a pinch of salt. If it still doesn’t dissolve, consult your pharmacist about another brand.