Stable heavy isotopes of hydrogen, carbon, and other elements have been incorporated into drug molecules, largely as tracers for quantitation during the drug development process. Deuteration has gained attention because of its potential to affect the pharmacokinetic and metabolic profiles of drugs[1].
References:
[1]. Russak EM, et al. Impact of Deuterium Substitution on the Pharmacokinetics of Pharmaceuticals. Ann Pharmacother. 2019;53(2):211-216.
[2]. Ping Li,et al. Natural and Enantiomeric Etiocholanolone Interact With Distinct Sites on the Rat alpha1beta2gamma2L GABAA Receptor. Mol Pharmacol. 2007 Jun;71(6):1582-90.
[3]. Dorota Zolkowska, et al. Anticonvulsant Potencies of the Enantiomers of the Neurosteroids Androsterone and Etiocholanolone Exceed Those of the Natural Forms. Psychopharmacology (Berl). 2014 Sep;231(17):3325-32.