Modeling Renal Clearance of Drugs- Application to Age-Related Pharmacokinetics of Daptomycin

The kidneys serve as the primary excretory organs responsible for eliminating endogenous waste products and xenobiotics, including pharmaceutical agents and their metabolites, through urine formation. Understanding the mechanistic basis of renal drug excretion is critical for optimizing therapeutic efficacy and minimizing toxicity. This paper provides an in-depth overview of the anatomical structure and functional dynamics of renal filtration, secretion, and reabsorption processes that govern drug clearance. Blood is delivered to the kidneys via the renal artery, and filtration begins at the glomerulus where small molecules pass into the nephron while larger components remain in circulation. The filtrate undergoes further refinement through selective tubular reabsorption and active secretion, culminating in urine formation. The role of the nephron in modulating drug excretion is modeled mathematically using key pharmacokinetic parameters, including the glomerular filtration rate (GFR), free drug fraction (fu), intrinsic tubular clearance, and the area under the plasma drug concentration-time curve (AUC). This work also presents fundamental equations describing renal clearance pathways and explores factors influencing drug reabsorption and secretion. Together, these insights offer a quantitative framework for predicting renal drug clearance and guiding rational drug design and dosage regimen development.