Vitamin K1-13C6 (Phylloquinone-13C6) is the 13C-labeled Vitamin K1. Vitamin K1 a naturally occurring vitamin required for blood coagulation and bone and vascular metabolism.In Vitro: 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.