Analysis of Azithromycin According to USP Method (ODP-50 4E)

Azithromycin is a 15-membered ring macrolide antibiotic. According to USP 39 method, azithromycin should be analyzed using a column packed with L67. It is necessary for the system suitability to satisfy resolution (Rs) between azithromycin and azaerythromycin of ≥ 3.0, tailing factor for azithromycin of 0.8 – 1.5 and relative standard deviation (RSD) of ≤ 1.1%. It was confirmed to satisfy all conditions when azithromycin and azaerythromycin were analyzed using Asahipak ODP-50 4E.

Sample : 10μL
Azithromycin
Azaerythromycin A
dissolved in 6.7g/L Dibasic potassium phosphate aq. (pH8.0 adjusted with phosphoric acid)/CH₃CN=40/60

Column       : Shodex Asahipak ODP-50 4E (4.6mmI.D. x 250mm)
Eluent       : 6.7g/L Dibasic potassium phosphate aq. (pH11.0 adjusted with 10M KOH)
               /CH3CN=40/60
Flow rate    : 1.0mL/min
Detector     : UV(210nm)
Column temp. : 40°C