Folinic Acid Impurity C, chemically defined as N-[4-[[(2-Amino-4-oxo-1,4-dihydropteridin-6-yl)methyl]amino]benzoyl]-L-glutamic acid and identical in structure to Folic Acid, is the fully oxidized (non-reduced) pteridine analog of Folinic Acid (Leucovorin), with molecular formula C₁₉H₁₉N₇O₆ and molecular weight 441.40 g/mol. Unlike the 5-formyl-5,6,7,8-tetrahydropteroyl core of the parent reduced-folate API, this compound retains a fully aromatic pteridine ring and no N5-formyl group. Because Calcium Folinate is manufactured chemically by reduction of Folic Acid to tetrahydrofolic acid followed by N5-formylation, this impurity typically reflects residual unreduced starting material, and it can also form by oxidative degradation of reduced folates. Given this close relationship, the compound is a critical reference marker for monitoring starting-material carryover, reduction completeness, and oxidative stability during Calcium Folinate (Leucovorin Calcium) API and injection manufacturing. Manufactured at Chemicea under precisely controlled synthetic and analytical protocols, this reference standard supports impurity identification, method validation (AMV), and QC testing in line with EP and USP pharmacopoeial requirements for Calcium Folinate. Each batch ships with a comprehensive Certificate of Analysis supported by HPLC and Mass Spectrometry data, ensuring reliable traceability for regulatory and R&D applications. CAS No. 59-30-3 | Explore complete technical documentation, Safety Data Sheet (SDS), and pricing.