W. Weber, L. Harnisch
Hoechst AG; Central Clin. Research, Clin. Pharmacology, P.O. Box 80 03 20, H 840, 6230 Frankfurt (M) 80
Population pharmacokinetic analysis of drugs belonging to the class of organic ions may use very similar physiologic models. Because of their polar nature they cannot penetrate biological membranes and therefore remain in the extra cellular fluid. Typical drugs of this class, like gentamicin and cefpirome, are not bound to plasma proteins and their renal clearance approximates the glomerular filtration rate (GFR), of patients. Age associated changes of the creatinine clearance, which is a substitute for the GFR, are well studied and already published. In the light of this knowledge, it is extremely important to differentiate between two types of normalisation concerning creatinine clearance, a) in terms of body weight and/or b) in terms of body surface area. The cefpirome population kinetic data deriving from patients of all ages (infants until adults age) reveal that the renal clearance of cefpirome is indeed proportional to the body surface area and approximates the typical GFR value of 120 ml/min/1,73m2. The surface normalised clearance model (Clearance = θ1 area) is, though to a minor extent, superior to the model using the proportionality of the renal clearance as a power function of weight (Clearance = θ1, weight θ2). Nevertheless both equations may be used as models for the determination of renal clearance in population kinetic analysis.
Reference: PAGE 2 () Abstr 910 [www.page-meeting.org/?abstract=910]
Poster: oral presentation