Question

Amikacin is a semi-synthetic derivative of
(A) Kanamycin
(B) Tobramycin
(C) Neomycin
(D) Gentamicin

• A. Kanamycin
• B. Tobramycin
• C. Neomycin
• D. Gentamicin

Hint:

Amikacin's chemical modification (adding an amino-hydroxybutyryl group to kanamycin) protects it from bacterial enzymes.
This makes it the aminoglycoside with the broadest spectrum of activity against resistant Gram-negative bacteria.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Aminoglycosides are a class of bactericidal antibiotics that inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit.
They include both naturally occurring compounds produced by soil microbes and semi-synthetic derivatives designed to resist bacterial resistance mechanisms.

Step 2: Detailed Explanation:
Let us identify the structural origins of amikacin:
- Amikacin is a semi-synthetic aminoglycoside antibiotic.
- It is synthesized by the acylation of the C-1 amino group of Kanamycin A with an L-(-)-4-amino-2-hydroxybutyryl side chain.
- This specific chemical modification protects the molecule from enzymatic inactivation by many bacterial aminoglycoside-modifying enzymes (acetyltransferases, phosphorylases, and adenylyltransferases).
- Consequently, amikacin has a broader spectrum of activity and is more resistant to bacterial degradation than its parent compound, kanamycin, or other aminoglycosides like gentamicin and tobramycin.

Step 3: Final Answer:
Amikacin is a semi-synthetic derivative of kanamycin. This corresponds to option (A).