What is an example of target-centered drug design?

• A. Synthesis of aspirin.
• B. Discovery of penicillin.
• C. The creation of Ritonavir.
• D. Development of insulin.

Answer: (C)

Target-centered drug design means building a molecule specifically to interact with a known biological target, using detailed knowledge of the target’s structure and mechanism to optimize binding, selectivity, and potency.

Ritonavir fits this approach because it was crafted to inhibit HIV-1 protease. Drug designers used structural information about the protease’s active site and substrate-binding pockets to create a molecule that mimics key features of the natural substrate and forms strong, specific interactions with the enzyme. The goal is to block the protease’s function with high affinity, which is the essence of targeting a particular protein with a designed inhibitor.

The other examples aren’t driven by designing against a specific molecular target in a guided, structure-based way. Synthesis of aspirin arose from understanding its mechanism (inhibition of cyclooxygenase) and optimizing it historically, but it isn’t a product of modern target-centered design. Discovery of penicillin was empirical, based on observing an antibacterial effect rather than designing against a defined target’s structure. Development of insulin is a hormone replacement approach rather than designing a molecule to modulate a specific enzyme or receptor.