The present invention provides a method for determining a level of a methotrexate
polyglutamate (MTXPG) in a cellular extract by resolving at least one MTXPG in
a cellular extract obtained from a human undergoing methotrexate therapy; and detecting
at least one resolved MTXPG, thereby determining a level of the resolved MTXPG.
A method of the invention can be useful, for example, for determining a level of
MTXPG3, MTXPG4 or MTXPG5 or for determining a
level of each methotrexate polyglutamate species (MTXPG1 to MTXPG7)
present in the cellular extract.
