Antipyrine pharmacokinetics and urinary excretion in female horses

Abstract

Objective - To measure renal clearance of antipyrine and urinary excretion of antipyrine (AP) metabolites in horses by use of validated high- performance liquid chromatography (HPLC) methods. Animals- 8 Standardbred mares. Procedure - HPLC methods for measurement of AP in equine plasma and AP and its metabolites in equine urine were validated. Antipyrine (20 mg/kg of body weight) was administered IV, and blood samples and urine specimens were collected over 24 hours. Results - Median plasma clearance of AP in horses was 6.2 ml/min/kg, of which <2% could be attributed to renal clearance. Urinary excretion of AP and its metabolites over 24 hours accounted for <22% of the AP dose administered. ..