High-pressure liquid chromatographic analysis of methotrexate in presence of its degradation products.

Two high-pressure liquid chromatographic methods are described for the quantitative determination of methotrexate in the presence of its contaminants and degradation products. Method 1 takes less than 15 min and is recommended for routine assays of methotrexate in commercial products. Method 2 takes about 35 min and is the method of choice to detect and quantitate large amounts of degradation products. Quantitation to a level of 1 microgram of methotrexate/ml is feasible by these methods and thus provides potential applicability for the analysis of methotrexate in biological fluids.