Which of the following is NOT listed as an example of a synthetic drug?

• A. Barbituric acid
• B. Salicylic acid
• C. Aspirin
• D. Penicillin

Answer: (D)

Synthetic drugs are those produced entirely by chemical reactions in the laboratory. A natural product is something made by living organisms or microorganisms.

Barbituric acid is a lab-made chemical used as a building block to synthesize barbiturate drugs, so it’s a clearly synthetic starting point. Salicylic acid can be found in nature but is also manufactured synthetically for drug production, so it’s not exclusively a natural product but is commonly produced through chemical methods. Aspirin is a drug created by chemical synthesis from salicylic acid, making it a synthetic compound.

Penicillin, however, is a natural product produced by a mold (Penicillium) during fermentation. While we can derive semisynthetic penicillins by modifying the natural molecule, the original penicillin itself is not a purely synthetic drug. That’s why it’s the example that is NOT listed as synthetic.