METHOTREXATE AND 7-HYDROXYMETHOTREXATE - SERUM LEVEL MONITORING BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

  • 1 January 1980
    • journal article
    • research article
    • Vol. 64  (1) , 165-169
Abstract
A reverse-phase high-performance liquid chromatographic assay with UV detection at 303 nm for methotrexate (MTX) and 7-hydroxymethotrexate (7-OH-MTX) in serum, plasma and CSF was developed. The procedure involves the concentration of MTX and 7-OH-MTX in the aqueous phase by an n-butanol-ether extraction, resulting in a sensitivity of 10-20 nM in serum. Serum levels of MTX correlated well with those obtained by a competitive dihydrofolate reductase binding assay (r [correlation coefficient] = 0.989). The clinical utility of the assay was demonstrated by measuring MTX and 7-OH-MTX serum levels in 42 patient samples.