(S)-2-(2,6-Dimethylphenyl)-3,3-dimethyl-d6-hexahydroimidazo[1,5-a]pyridin-1(5H)-one is the labeled analogue of (S)-2-(2,6-Dimethylphenyl)-3,3-dimethylhexahydroimidazo[1,5-a]pyridin-1(5H)-one (D447430), an impurity of R674990), a metabolite of (S)-Ropivacaine (R674995), that acts as a local anaesthetic for use during medical procedures. Frequently used in epidural procedures as a labor analgesia.