Azithromycin is a 15-membered macrolide antibiotics. According to US Pharmacopeia (USP), HPLC analysis of azithromycin injection should be done using a column and a guard column filled with L67 packing material. The system suitability requires the resolution between azithromycin and azaerythromycin A to be ≥ 2.5; tailing factor of the azithromycin to be between 0.9 and 1.5; and relative standard deviation (RSD) of azithromycin peak area to be ≤ 2.0 %. Use of Asahipak ODP-50 4E and ODP-50G 4A (guard column) was confirmed to satisfy all required conditions for the analysis.
Sample : 15 μL
1. Azaerythromycin A 1 mg/mL
2. Azithromycin 1 mg/mL
dissolved in H2O/CH3CN=48/52
Column : Shodex Asahipak ODP-50G 4A (4.6 mm I.D. x 10 mm) + ODP-50 4E (4.6 mm I.D. x 250 mm) Eluent : 6.7 g/L Dibasic potassium phosphate aq./CH3CN=48/52 (adjusted to pH 11.0 with 10 M KOH aq.) Flow rate : 1.0 mL/min Detector : UV (215 nm) Column temp. : 40 °C