[Bioavailability of drugs--concepts and problems]

Area of Science:

• Pharmacokinetics and Biopharmaceutics
• Drug Development and Evaluation

Context:

• The concept of bioavailability is central to drug efficacy and safety.
• Current literature reveals inconsistencies in the definition and practical application of bioavailability.
• Distinguishing bioavailability from absorption is crucial for accurate interpretation of drug performance.

Purpose:

• To critically review and refine the definition of bioavailability.
• To highlight the divergence between theoretical definitions and practical determinations of bioavailability.
• To propose a clearer framework for understanding drug absorption and disposition.

Summary:

• The paper examines the evolution of bioavailability definitions, identifying practical discrepancies.
• It differentiates bioavailability from the extent of drug absorption.
• The study advocates for precise terminology, separating in vitro dissolution, in vivo liberation, and absorption stages.
• It stresses the importance of including animal studies in pharmacokinetic-biopharmaceutical investigations.

Impact:

• A clearer understanding of bioavailability enhances drug development processes.
• Standardized terminology improves the reliability and reproducibility of biopharmaceutical studies.
• This work provides a foundation for more accurate drug performance assessments.