Question

Match List I with List II:
List I
A. Cotrimoxazole
B. Silver sulfadiazine
C. Long acting sulfonamide
D. Quinolones
List II
I. Nalidixic acid
II. Sulfadoxine
III. Used topically as 1% cream
IV. Trimethoprim and sulfamethoxazole
Choose the correct answer from the options given below:

• A. A-II, B-I, C-III, D-IV
• B. A-IV, B-III, C-II, D-I
• C. A-III, B-II, C-I, D-IV
• D. A-I, B-III, C-IV, D-II

Hint:

Remember that Silver Sulfadiazine is standardly used as a 1% burn cream in veterinary clinics. Matching B-III immediately isolates the correct option.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Sulfonamides are synthetic antimicrobial agents containing the sulfonamide chemical group.
They are classified based on their absorption, duration of action, and intended route of administration.
To enhance their efficacy and prevent the development of bacterial resistance, they are frequently combined with dihydrofolate reductase inhibitors (sequential blockade) or modified for topical application.

Step 2: Detailed Explanation:
Let us analyze each pair in the matching list:
1. Cotrimoxazole (A):
Cotrimoxazole (co-trimoxazole) is a synergistic combination of Trimethoprim and sulfamethoxazole (IV) in a fixed $1:5$ ratio.
This combination produces a sequential blockade in bacterial folic acid synthesis, converting two bacteriostatic drugs into a bactericidal combination.
Thus, A matches with IV.
2. Silver sulfadiazine (B):
Silver sulfadiazine is a highly effective topical antimicrobial agent.
It is widely formulated and used topically as 1% cream (III) to prevent and treat bacterial infections in second- and third-degree burns.
Thus, B matches with III.
3. Long acting sulfonamide (C):
Sulfonamides are classified by half-life.
Sulfadoxine (II) is a classic example of an ultra-long-acting sulfonamide, with a half-life of up to several days in most domestic animals, allowing for infrequent dosing intervals.
Thus, C matches with II.
4. Quinolones (D):
The quinolones are a family of synthetic broad-spectrum antibacterial drugs.
Nalidixic acid (I) is the prototype first-generation quinolone, primarily used historically for urinary tract infections.
Thus, D matches with I.
Combining these matches, we get: A-IV, B-III, C-II, D-I.

Step 3: Final Answer:
The correct matching sequence is A-IV, B-III, C-II, D-I.
Therefore, the correct option is (B).