What are two types of computer-aided drug design (CADD)?

• A. Structure Based Drug Design And Ligand Based Drug Design
• B. Pharmacokinetic And Pharmacodynamic Modeling
• C. QSAR And Docking
• D. De Novo And Fragment-Based Design

Answer: (A)

In computer-aided drug design, two main categories guide how molecules are planned: structure-based drug design and ligand-based drug design. Structure-based design uses the three-dimensional structure of the biological target to guide how a candidate fits into the binding site. Techniques like docking, virtual screening, and evaluation of binding interactions fall here, and they rely on knowing or predicting how the target protein is shaped and where it can interact with a ligand. Ligand-based design, on the other hand, does not depend on the target’s structure. Instead, it uses information from known active compounds to infer what chemical features are important for activity, often through pharmacophore modeling, QSAR, and similarity searches. These approaches help identify or optimize new ligands when the target structure is unavailable or uncertain.

The other options mix up specific methods or related fields. Pharmacokinetic and pharmacodynamic modeling deals with how a drug moves through and affects the body—important for development, but not a primary category of designing new molecules. QSAR and docking are representative techniques used within the two main categories but do not themselves define the broad classifications. De novo and fragment-based design are design strategies that can be applied within either category, depending on how they're used, but they don’t contrast the two overarching approaches as clearly.