title: Plasma antipyrine half-life can be determined from urine data.
abstract: Antipyrine half-life has been determined from measurements of antipyrine concentrations in spontaneously voided urine specimens in eleven subjects, studied on a total of forty-seven different occasions while receiving no drugs, interferon or ketoconazole. Plasma and saliva half-lives show good intrasubject correlation. Plasma and urine half-lives show good intrasubject correlation provided total urine output is at least 1.1 l day-1. The range of intrasubject correlation coefficients for plasma and urinary half-lives was 0.76 to 0.98, with a median value of 0.85. Saliva and urine half-lives show good intrasubject correlation, with the range of intrasubject correlation coefficients from 0.74 to 0.98, and with a median value of 0.75. There is a small but consistent bias towards shorter urinary half-life estimates; this averaged 0.75 h for the plasma-urine studies and 0.192 h for the saliva-urine studies. There were parallel changes in antipyrine half-life estimated from plasma and urine for one of our subjects who received multiple doses of recombinant beta-interferon and had a 150% increase in antipyrine half-life over the study period.
mesh_terms: D000328:Adult; D000368:Aged; D000983:Antipyrine / Q000097:blood* / Q000652:urine; D005260:Female; D006207:Half-Life; D006801:Humans; D007372:Interferons / Q000494:pharmacology; D007654:Ketoconazole / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D012463:Saliva / Q000032:analysis
chemical_list: D007372:Interferons; D007654:Ketoconazole; D000983:Antipyrine