Distribution Clearance: Significance and Underlying Mechanisms.

Area of Science:

• Pharmacokinetics and Drug Metabolism
• Physiological Modeling
• Quantitative Pharmacology

Background:

• Distribution kinetics is an under-explored area within pharmacokinetics.
• Mammillary compartmental models are frequently employed in pharmacokinetic analyses.
• Understanding drug distribution is crucial for optimizing therapeutic outcomes.

Purpose of the Study:

• To assess the utility of the model-independent parameter, whole body distribution clearance (CLD), for evaluating drug distribution kinetics.
• To explore the physiological underpinnings of drug distribution using CLD.
• To compare the distributional properties of various drugs.

Main Methods:

• Calculated whole body distribution clearance (CLD) using parameters from mammillary compartmental models for 15 drugs.
• Investigated distribution processes by examining relationships between CLD, pharmacokinetic parameters, and covariates.
• Utilized the model-independent nature of CLD for comparative analyses.

Main Results:

• Model-independent CLD facilitated comparisons of drug distribution and provided physiological insights.
• Significant alterations in CLD were observed due to drug-drug interactions.
• CLD changes were also noted in relation to transporter polymorphisms and disease states.

Conclusions:

• Whole body distribution clearance (CLD) is a valuable parameter for assessing drug distribution kinetics.
• Estimating CLD as an adjunct to clearance and steady-state volume of distribution is recommended.
• CLD enhances the understanding of drug distribution in various physiological and pathological conditions.