Displaying 3 results of Quinapril Stable Isotopes Quinapril is a medication used to treat hypertension and heart failure. Quinapril stable isotopes refer to non-radioactive forms of quinapril that have the same number of protons and neutrons in their nuclei. These isotopes are useful in pharmacokinetic and pharmacodynamic studies of quinapril, as well as in the development of new drug formulations.