Pharmacopoeial isocratic HPLC/UV method for the determination of the cephalosporin antibiotic cefazolin sodium (CAS 27164-46-1), on an ARION® Polar C18, 5.0 µm column (250 mm × 4.6 mm, ARI-5721-LM46). Mobile phase A: ACN and B: 2.77 g/L disodium hydrogen phosphate dodecahydrate + 1.86 g/L citric acid monohydrate, A : B 10/90 (v/v), flow rate 1.0 mL/min, UV detection at 270 nm, injection volume 20 µL. The system suitability requirement (resolution minimum 2.0 between cefazolin and cefuroxime in reference solution (b)) is met, with cefuroxim at about 26.5 min and cefazolin at about 29.5 min.