Quantitation and urinary pattern of 4,4′-dihydroxyantipyrine, 4-hydroxy-antipyrine and 3-hydroxymethyl-antipyrine, as main metabolites of antipyrine in man and rat

Abstract

A t.l.c.-assay has been developed for the simultaneous determination from the urine of man and animals of three major hydroxylated metabolites of antipyrine (4,4'-dihydroxy-antipyrine, 4-hydroxy-antipyrine, 3-hydroxymethyl-antipyrine). The methodology is also applicable to bile fluid, liver perfusate and liver homogenate. Genuine conjugates are cleaved by acid hydrolysis and free, acid stable metabolites are extracted. Extracts are subjected to t.l.c. and the chromatograms analysed quantitatively by u.v.-reflectance measurements using authentic materials as standards. Calibration curves are linear with a correlation coefficient r greater than 0.990. Recovery for each metabolite is greater than 95%. Reproducibility of the method is good, with variation coefficients in the range of 3-7%, depending on concentration. The sensitivity of the method is sufficient for practical needs. The specificity of the procedure was confirmed using radio-labelled antipyrine. In man, 4-hydroxy-antipyrine is the principal hydroxylation product in this series, accounting for about 35-40% of the dose. 3-Hydroxymethyl-antipyrine makes up for about 13-17% and 4,4'-dihydroxy-antipyrine represents 3-6% of the dose of antipyrine. In the rat, 4-hydroxy-antipyrine accounts for about 15-31%, 3-hydroxymethyl-antipyrine for 22-28% and 4,4'-dihydroxy-antipyrine for up to 11-18% of the dose. Variation of this pattern in different strains is moderate. In both species, the major portion of phase-I metabolites is excreted as conjugates. Part of them appears in a free form.

Antipyrine metabolite kinetics in healthy human volunteers during multiple dosing of phenytoin and carbamazepine.

“…The control urinary 4H recoveries reported in this study (36.1 ± 4.7 and 31.5 ± 8.5% of dose for the phenytoin and carbamazepine studies, respectively, before treatment) are slightly higher than those reported by some workers (Danhof et al, 1982b;Toverud et al, 1981) but are of the same order (38.3 ± 2.0%) as reported by Bottcher et al (1982). Both 3HM (12.5 + 2.0% and 12.1 + 2.0%) and Nor (15.5 ± 3.3% and 13.6 + 4.6%) control recoveries are of similar magnitudes to those previously reported.…”

“…4,4'-dihydroxyantipyrine is a metabolite of antipyrine found in significant amounts after antipyrine dosing in man (Bottcher et al, 1982) and the formation of this metabolite may therefore contribute to the CLRes. This metabolite has also been noted to respond to induction in rats in a similar manner to 4-hydroxy-antipyrine (Teunissen etal., 1983a, b) and analogous behaviour may partially explain the increases in CLReS in the present studies.…”

Determination of antipyrine sulphoconjugates in isolated cultured rat hepatocytes

“…Although determination of conjugated metabolites of antipyrine after hydrolysis is a standard procedure (Boettcher et al 1982a, Eichelbaum et a2. 1981, Teunissen et al 1983, the instability of the deconjugated metabolites indicates that this is unsatisfactory.…”

Crystal structure of 3,4-dihydroxy-1,5-dimethyl-2-phenylpyrazolium chloride, [C11H13N2O2]Cl

“…Discussion 4-Hydroxyantipyrine is one of the main metabolites of antipyrine in man and rat [1]. Together with 3-hydroxyantipyrine and 4,4'-dihydroxyantipyrine, they are excreted in free form or as glycoconjugates [2].…”