Which compound is not classified as an aminoglycoside?

Aminoglycosides are a class of antibiotics primarily used to treat serious infections caused by aerobic gram-negative bacteria. They work by inhibiting bacterial protein synthesis, which is essential for the growth and multiplication of bacteria.

Gentamicin, tobramycin, and neomycin are all classified as aminoglycosides; they all share similar structures and mechanisms of action, targeting the ribosomal subunit of bacteria. These compounds are often used in clinical settings for their potent effects against certain pathogens, particularly in hospital settings where multidrug-resistant bacteria might be present.

Ampicillin, on the other hand, is a penicillin-type antibiotic that belongs to the beta-lactam class. It works by inhibiting cell wall synthesis, which is a completely different mechanism compared to the action of aminoglycosides. Due to its distinct class and mechanism, ampicillin does not fall under the aminoglycoside classification, making it the correct answer to this question.