[Determination of nonmetabolized antipyrine in human urine]

A method for evaluating the renal clearance of antipyrine is proposed. The analyses were performed for a group of healthy females of reproductive age. The renal clearance of nontransformed antipyrine is found to be significant and the basic indices of renal activity (diuresis, creatinine excretion) are correlated with the drug concentration in saliva. A single administration of antipyrine in a dose of 10 mg/kg does not influence the renal function of healthy volunteers. The proposed photometric method of antipyrine determination in urine (under the conditions of loading with 0.5% NaCl solution at an amount of 0.5% of body weight) is sufficiently sensitive and provides information about the renal clearance of antipyrine, offering an important supplement to the data obtained by conventional methods.