Determination of the "chromatographic pattern" for the identification of dipyrone urinary metabolites.

Sodium [N-(1,5-dimethyl-3-oxo-2-phenylpyrazolin-4-yl)-N-methylamino] methanesulfonate (dipyrone) cannot be detected as such in biological fluids since absorption is preceded by hydrolysis to 4-methylaminoantipyrine, which is actually absorbed and further metabolized. In the present work standardized TLC Rf values and gas chromatographic retention indices for the four main urinary metabolites of dipyrone were determined. Inclusion of these parameters in the principal component analysis "scores plot" allows dipyrone to be included as a possible candidate in the not oriented search for unknown drug assumption in cases of overdose intoxication or poisoning.