Notes: Pyridoxine-d3 is intended for use as an internal standard for the quantification of pyridoxine (Item No. 20706) by GC- or LC-MS. Pyridoxine is a 4-methanol form of vitamin B6 that is converted to pyridoxal 5’-phosphate (Item No. 20352), the active form of vitamin B6 and an important cofactor for metabolism.{32678} Pyridoxine has been used in cell culture media as a precursor to pyridoxal 5’-phosphate.{45213}