| abstract |
Crystalline calcium salt of (6R,S)-, (6R)- and (6S)-tetrahydrofolic acid. Also claimed is the magnesium salt. The crystallisation is preferably performed in a polar medium, preferably water or a mixture of water and an organic solvent most preferably acetic acid or a lower alcohol, at pH 7-10 at an elevated temperature and/or from a dilute solution |