Displaying 6 results of Orphenadrine Stable Isotopes Orphenadrine stable isotopes are a class of chemical compounds that have been specifically labeled with stable isotopes for use in medical research. These isotopes have the same number of protons and electrons as their non-labeled counterparts, but differ in their number of neutrons. Orphenadrine stable isotopes are useful for studying the pharmacokinetics and metabolism of orphenadrine, a muscle relaxant medication used to treat painful muscle spasms. Researchers use these isotopes to track the movement of orphenadrine in the body and gain a better understanding of its therapeutic effects.