A STUDY OF THE ANALYSIS OF THE URINARY EXCRETION OF ANTIMICROBIAL AGENTS AND THE PREDICTION OF THEIR URINARY LEVEL IN PATIENTS

Abstract

A possibility of theoretical presumption of urinary level of antimicrobial agents substituting for measurement of real urinary concentration was studied. Intravenous bolus injection of gentamicin (GM), ampicillin (ABPC) or cefoperazone (CPZ) was utilized in 72 cases, and urinary and serum concentration of these three antibiotics were measured. The urine time-course data of GM and ABPC but CPZ, which is excreted by hepatobiliary rather than renal elimination, revealed biexponential and were fitted to a two compartment open model when urine specimens were collected paritively and attentively especially during 1 hour after injection. However, correction of the data by creatinine clearance of individual patients and some parameters drawn from the pharmacokinetic analysis produced a more suitable formula to estimate urine levels and even in CPZ this two compartment open model was available for analysis of urine pharmacokinetics. Estimation of the urine level from the serum level was also successful. It was concluded that estimation of the urine level by a formula without complex real detection of urine concentrations in individuals could be feasible and under some conditions it would be possible from serum pharmacokinetics. This estimated values must be of use in treatment of urinary tract infections.