Azithromycin is a 15-membered ring macrolide antibiotic. According to the United States Pharmacopeia and the National Formulary (USP 42-NF 37*), "ASSAY" for "Azithromycin for Injection" should be carried out with a analysis column and its guard column filled with L67 packing material. The Asahipak ODP-50 4D and ODP-50G 4A (guard column) filled with L76 packing material, in series confirmed the requirements were met.

System suitability requirementsResolution between azithromycin A and azaerythromycin (System suitability solution): ≥ 2.5
Tailing factor (Standard solution): 0.9 - 1.5
Relative standard deviation (RSD) (Standard solution): ≤ 2%

*The version at the time of the application acquisition.

Sample: 15 µL
(Standard solution) 1 mg/mL of Azaerythromycin in H₂O/CH₃CN=48/52
(System suitability solution) 1 mg/mL each of Azaerythromycin A and Azithromycin in H₂O/CH₃CN=48/52

1. 1.Azaerythromycin A
2. 2.Azaerythromycin