Displaying 3 results of Pseudoephedrine Stable Isotopes Pseudoephedrine stable isotopes are non-radioactive forms of the drug pseudoephedrine. These isotopes are used in research and analytical applications to study the metabolism, pharmacokinetics, and drug interactions of pseudoephedrine. They are also used in forensic science to distinguish between illicit and legitimate sources of pseudoephedrine. The stable isotopes of pseudoephedrine are chemically identical to the naturally occurring form of the drug, but their atomic composition is different, allowing for precise tracking and measurement.