Azithromycin

Also known as: Zithromax, Azithral, Z-Pack, Azee, Zady

CAS Number: 83905-01-5

Azalide macrolide antibiotic

Pharmacopeia Standards

USPBPEPIP

Mechanism of Action

Azalide (15-membered ring macrolide) that binds the 50S ribosomal subunit (23S rRNA peptidyl transferase domain), blocking peptide translocation and inhibiting protein synthesis. Bacteriostatic at usual concentrations. Unique pharmacokinetics: massive tissue distribution (Vd ~31 L/kg), high intracellular accumulation (especially macrophages and PMNs), prolonged tissue half-life (~68 hours) enables 3–5 day courses with extended post-antibiotic effect.

Technical Specifications

Generic / INN Name	Azithromycin
CAS Registry Number	83905-01-5
Molecular Formula	C38H72N2O12
Molecular Weight	748.98 g/mol
Typical Purity	97.0–102.0%
Storage Conditions	Store below 30°C, protected from light
Shelf Life	36 months from date of manufacture
Category	Macrolides

Specifications are indicative and intended for sourcing reference only. Always confirm against the supplier's Certificate of Analysis and the applicable pharmacopeial monograph before issuing a purchase specification.

Typical Applications

Community-acquired pneumonia (atypical — Mycoplasma pneumoniae, Chlamydophila, Legionella), pharyngitis/tonsillitis (penicillin-alternative), COPD exacerbations (atypical coverage), Chlamydia trachomatis (single 1g dose — first-line), MAC prophylaxis in HIV patients, traveler's diarrhea, typhoid (alternative), pelvic inflammatory disease (with other agents), pertussis prophylaxis/treatment.