High-performance liquid chromatographic assay of methotrexate, 7-hydroxymethortrexate, 4-deoxy-4-amino-N10-methylpteroic acid and sulfamethoxazole in serum, urine and cerebrospinal fluid.

D A Cairnes, W E Evans

Index: J. Chromatogr. A. 231(1) , 103-10, (1982)

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Abstract

An automated high-performance liquid chromatographic system is described for separation and quantitation of the antineoplastic drug methotrexate and metabolites, and the antibiotic sulfamethoxazole in body fluids. The 40-min analysis utilizes a reversed-phase C18 column and gradient elution with detection by absorbance of ultraviolet light at 308 nm. The minimum detectable quantities with this assay are: methotrexate 4.4 ng (9.8 X 10(-12) mole); 4-deoxy-4-amino-N10-methylpteroic acid 11.9 ng (3.7 X 10(-11) mole); 7-hydroxymethotrexate 30 ng (6.5 X 10(-11) mole); sulfamethoxazole 125 ng (4.9 X 10(-10) mole). This analytical method should prove useful for therapeutic monitoring and pharmacokinetic studies of these compounds.