Bioavailability and ADMET

This review discusses the fundamental concepts and recent advancements in bioavailability and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity), which are critical parameters in drug discovery and development. Bioavailability determines the proportion of an administered drug that reaches systemic circulation in its active form, while ADMET collectively defines the pharmacokinetic and toxicological behavior of a compound within the body. Understanding these factors is essential for predicting the therapeutic performance, safety, and clinical success of new drug candidates. Key models such as Lipinski’s Rule of Five, Veber’s Rules, and the Bioavailability Score (BAS) are used to estimate drug likeness and absorption potential, providing a scientific basis for rational compound selection. The integration of in silico tools, including SwissADME, pkCSM, ADMETlab, and admetSAR, has revolutionized early-stage drug evaluation by enabling accurate and cost-effective prediction of pharmacokinetic properties and toxicity risks. Moreover, combining computational approaches with experimental validation enhances the reliability of drug screening and minimizes late-stage development failures. Overall, this review emphasizes the importance of incorporating bioavailability and ADMET assessment into the early phases of drug design to ensure the discovery of effective, safe, and clinically viable therapeutic agents, ultimately improving the efficiency and success rate of modern pharmaceutical research.