Fragment-Based Drug Discovery: Opportunities and Challenges in Pharmaceutical Chemistry

Fragment-based drug discovery (FBDD) has become a revolutionary model in pharmaceutical chemistry, providing a logical and effective substitute for traditional high-throughput screening (HTS) methods. This detailed review explores the principles, methods, uses, and obstacles of FBDD in contemporary drug development. Using low-molecular-weight compounds (generally 150–300 Da following the "rule of three") as foundations, FBDD facilitates a methodical investigation of extensive chemical space, enhancing binding efficiency and shortening development periods. This review examines a range of screening technologies such as nuclear magnetic resonance (NMR) spectroscopy, surface plasmon resonance (SPR), X-ray crystallography, and thermal shift assays. We outline strategies for fragment optimization—such as growing, linking, and merging techniques—and emphasize successful clinical applications, featuring eight FDA-approved medications and more than 50 compounds currently in clinical trials. Recent developments in targeting protein-protein interactions (PPIs), allosteric modulation, and the incorporation of artificial intelligence and machine learning are analyzed. FBDD offers considerable potential for identifying new therapeutic compounds, especially for targets that were previously considered "undruggable," but it also faces challenges such as weak initial binding affinities, a need for precise detection techniques, and intricate optimization procedures. This review consolidates existing insights and future outlooks on FBDD, establishing it as an essential instrument in modern pharmaceutical chemistry and drug development.