Azithromycin is a chemical structure representative of which class?

• A. Macrolides
• B. Cephalosporin
• C. Penicillin
• D. Quinolones

Answer: (A)

Azithromycin is a macrolide antibiotic, a class defined by a large macrocyclic lactone ring. Drugs in this group bind reversibly to the 50S ribosomal subunit (specifically the 23S rRNA) and block the translocation step of protein synthesis, halting elongation. Azithromycin is a 15‑membered ring azalide derived from erythromycin, which gives it improved acid stability, better tissue penetration, and a longer half-life. These features distinguish it from other antibiotic classes such as beta‑lactams (cephalosporins and penicillins) and fluoroquinolones, which have different structures and mechanisms of action.