Some pitfalls in selecting descriptive pharmacokinetic models.
Some pitfalls in selecting pharmacokinetic models are enumerated. To calculate the pharmacokinetic parameters of a drug that exhibits a biphasic convex plasma concentration-time curve, a two-compartment model does not automatically have to be applied. When only the parent drug in plasma is considered, a two-compartment model seems to be most appropriate. However, when the kinetic behavior of the metabolite has to be taken into account, and when a metabolic equilibrium underlies the metabolic elimination, the two-compartment model may not be appropriate. Also, when calculating the kinetic parameters of a drug with a concave biphasic plasma concentration-time curve, a capacity-limited metabolic conversion is not the automatic explanation for this observation. Limitations in renal excretion and bioavailability may be the reasons for this behavior. Convex and concave biphasic plasma concentration-time curves are illustrated, using sulfonamides as test compounds.
D003460:Crystallization; D004358:Drug Therapy; D006801:Humans; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D004364:Pharmaceutical Preparations / Q000097:blood / Q000378:metabolism* / Q000652:urine; D006435:Renal Dialysis; D013997:Time Factors
D004364:Pharmaceutical Preparations