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Kinetics and metabolism of pyrazolones (propyphenazone, aminopyrine and dipyrone).
Author(s) -
Volz M,
Kellner HM
Publication year - 1980
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.1365-2125.1980.tb01813.x
Subject(s) - chemistry , metabolite , oral administration , metabolism , microgram , urine , pharmacokinetics , demethylation , pharmacology , volume of distribution , chromatography , biochemistry , in vitro , medicine , gene expression , dna methylation , gene
1 Propyphenazone 220 mg was administered orally to volunteers. Maximum plasma concentrations between 1.5 microgram/ml and 3.5 micrograms/ml were found 30 min later. After comparable doses plasma concentrations in dog and rabbit were lower. The distribution volumes were 2 l/kg. 2 The major metabolic route of propyphenazone is demethylation. The main urinary metabolite is the enolglucuronide of N‐(2)‐ demethylpropyphenazone. 3 Aminopyrine is rapidly and almost completely absorbed after oral administration. Maximum plasma concentrations of 10 microgram/ml are reached 1.5 h after a 500 mg dose. The biological half‐ life is 2‐3 h, the relative distribution volume 60% on average, and binding to plasma proteins approximately 15%. 4 Unchanged aminopyrine is only excreted in small quantities. The major routes of metabolism are demethylation (4‐methylaminoantipyrine and 4‐aminoantipyrine) and acylation (4‐acetyl and 4‐formylaminoantipyrine). There are other biotransformation products. 5 After oral administration of [14C]‐ dipyrone 480 mg the maximum serum concentration of 13.4 +/‐ 0.8 microgram/ml occurred at 1‐1.5 hours. 6 Dipyrone was not detectable in serum or urine. Four of seven metabolites were identified, and were identical with the main metabolites of aminopyrine.