Experimental evaluation of in vivo antibacterial activities and safety of azithromycin fumarate in mice

Objective: To evaluate the in vivo antibacterial activities and safety of azithromycin fumarate(AMF) in comparision with azithromycin(AM) and erythromycin(EM).Methods: The mice general infection models were established by intraperitoneal injecting Staphylococcus aureus and Streptococcus hemolyticus,respectively.And the protective effects of AMF,AM and EM administered intragastically against the mice infected were investigated.After single intragastric dosing,the toxic symptoms and the number of deaths of azithromycin fumarate were observed for seven days in normal mice.Results: The ED50 values of AMF in mice infected by Staphylococcus aureus and Streptococcus hemolyticus were 33.38 and 18.25 mg?kg-1,AM were 58.22 and 17.81 mg?kg-1,EM were 116.92 and 47.51 mg?kg-1,respectively.The LD50 value of AMF administered intragastically was 3273.4 mg?kg-1 in normal mice.The chemotherapeutic indexes of AMF were 98.1 and 179.4 in mice infected by Staphylococcus aureus and Streptococcus hemolyticus.Conclusion: AMF and AM showed higher in vivo antibacterial activity against mice infected by Staphylococcus aureus and Streptococcus hemolyticus than EM.The protective effects of AMF against the mice infected by Staphylococcus aureus was better than AM,and both of them have similar effects on the mice infected by Streptococcus hemolyticus.