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Pharmacokinetics of single doses of sulphinpyrazone and its major metabolites in plasma and urine.
Author(s) -
Bradbrook ID,
John VA,
Morrison PJ,
Rogers HJ,
Spector RG
Publication year - 1982
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.1982.tb01353.x
Subject(s) - urine , pharmacokinetics , metabolite , chemistry , sulfinpyrazone , active metabolite , half life , pharmacology , chromatography , medicine , biochemistry , aspirin
1 High pressure liquid chromatographic assays for the estimation of sulphinpyrazone and its sulphide, sulphone and p‐hydroxy metabolites in plasma and urine are described. 2 Five normal volunteers received 200 mg and 400 mg sulphinpyrazone orally. Sulphinpyrazone was rapidly absorbed and eliminated with a half‐life of approximately 4 h irrespective of dose. Peak plasma concentrations and area under the plasma concentration‐time curves (AUC) were consistent with linear pharmacokinetic behaviour. 3 Plasma concentrations of the sulphone were low and peaked before those of the sulphide; its mean half‐life was 3.1 h. The sulphide, which may be the sulphinpyrazone metabolite with activity on platelets, was eliminated with a mean half‐life of 13.4 h. The AUC increases with dose of both metabolites suggested non‐ linearity. 4 Approximately 45‐50% of the administered dose was eliminated in the urine as unchanged drug or as sulphone or p‐hydroxy‐ sulphinpyrazone. The sulphide metabolite was not detected in the urine. The renal clearance of sulphinpyrazone was approximately 18 ml min‐1 and that for the sulphone was similar. Sigma minus plots of the urinary excretion yielded half‐lives of 3.5 h for the sulphone and 1 h for p‐ hydroxy‐sulphinpyrazone.