Question

Which of the following is first prodrug for sulfonamide:

• A. Prontocil
• B. Sulfamidochrysodine
• C. Sulfatrim
• D. Trimethoprim

Answer 1

The Correct Option is A

The correct option is (A): Prontocil.

Answer 2

The question asks which compound was the first prodrug developed for the sulfonamide class of drugs. Let's check each option.

1. Prontocil: Prontocil, correctly known in the pharmaceutical literature as Prontosil, is a red azo dye that, on its own, has no antibacterial action in a test tube. Once given to a patient, however, the body's enzymes reductively cleave its azo bond, releasing sulfanilamide, the actual active antibacterial agent. Because the dye itself is inactive and needs to be metabolised into the true drug, Prontocil is recognised as the first sulfonamide prodrug, and its discovery in the 1930s opened the entire sulfa drug era.
2. Sulfamidochrysodine: This is simply another name historically used for Prontocil itself in some early literature, rather than a separate, distinct compound with its own claim to being first.
3. Sulfatrim: Sulfatrim is a combination product of sulfamethoxazole and trimethoprim, developed decades after the original sulfa drugs, so it cannot be the first prodrug of the class.
4. Trimethoprim: Trimethoprim is not a sulfonamide at all; it is a diaminopyrimidine that is often combined with a sulfonamide to give a synergistic antibacterial effect, but it belongs to a different chemical class.

The compound that fits both requirements, being inactive itself and metabolised into the active sulfa drug, and being the first such compound discovered, is Prontocil.

So the correct answer is Prontocil.