7 but above the natural abundance only partial deuteration of one site is required thus less than about 7 enrichment would still refer to deuterium enriched levetiracetam with the natural abundance of deuterium being 0 015 one would expect that for approximately every 6 667 molecules of levetiracetam 1 0 00015 6 667 there is one naturally occurring molecule with one deuterium present since levetiracetam has 14 positions one would roughly expect that for approximately every 93 338 molecules of levetiracetam 14 u00d7 6 667 all 14 different naturally occurring mono deuterated levetiracetams would be present this approximation is a rough estimate as it doesn 39 t take into account the different exchange rates of the hydrogen atoms on levetiracetam for naturally occurring molecules with more than one deuterium the numbers become vastly larger in view of this natural abundance the present invention in an embodiment relates to an amount of an deuterium enriched compound whereby the enrichment recited will be more than naturally occurring deuterated molecules in view of the natural abundance of deuterium enriched levetiracetam the present invention also relates to isolated or purified deuterium enriched levetiracetam the isolated or purified deuterium enriched levetiracetam is a group of molecules whose deuterium levels are above the naturally occurring levels e g 7.