OCCURRENCE AND SIGNIFICANCE OF D-METHOTREXATE AS A CONTAMINANT OF COMMERCIAL METHOTREXATE

  • 1 January 1984
    • journal article
    • research article
    • Vol. 44  (5) , 1843-1846
Abstract
Methotrexate from various commercial sources contained 0.5-48% (wt/wt) of the enantiomer D-methotrexate. The 2 methotrexate enantiomers were separated by using chiral high-performance liquid chromatography with an octadecyl silica column and a mobile phase containing L-proline and cupric nitrate. For the assay of D-methotrexate impurity in commercial methotrexate, L-methotrexate was hydrolyzed with carboxypeptidase G1, and the remaining D-methotrexate was quantitated by high-performance liquid chromatography. The biological effects of D-methotrexate were investigated and compared to that of L-methotrexate. D-Methotrexate as a good inhibitor of dihydrofolate reductase from both murine and human tumor cells, but was a poor inhibitor of L1210 and CCRF-CEM cell growth. In animal experiments with dogs and mice, D-methotrexate was rapidly absorbed from the intestine and excreted by the kidneys.