A population pharmacokinetic model for creatinine with and without ingestion of a cooked meat meal

A population pharmacokinetic (PPK) model for creatinine was successfully developed using creatinine concentration data from 6 healthy male volunteers with and without ingestion of 225 g boiled beef as an exogenous creatinine source. A model with first-order absorption, zero-order creatinine generation, and first-order elimination was used to describe the pharmacokinetic (PK) data. Creatinine parameters, estimated from the final model were: apparent absorption rate constant (Ka, 1.71 1/h), lag time (0.343 h), renal clearance (equal to systemic clearance) (CL, 7.57 L/h), apparent volume of distribution (Vd, 52.8 L), and creatinine generation rate (CGR, 67.8 mg/h). The CL and CGR estimates were in agreement with the reported values, whereas the Vd estimates were slightly higher than the reported values. The model is a useful starting point for further experimental approaches to improve the understanding of creatinine kinetics, which may involve creatinine “dosing” accompanied by independent methods to assess the glomerular filtration rate.