Safety Evaluation And Phase Ⅱ Clinical Trial Of Gamithromycin Injection In Calves

Objective:Gamithromycinin is a novel semi-synthetic macrolide veterinary antibiotic,which can effective suppression of Pasteurella multocida,Mycoplasma bovis and Maniella haemolyticus,which cause respiratory diseases in cattle,Its bioavailability is high,and it can reach high concentration in target organ lung tissue,this medicine is widely used in the treatment of bovine respiratory diseases abroad and has a bright future.There is a high incidence of respiratory diseases in some pasture calves in China,so it is an urgent need to develop new veterinary drugs.This experiment scientifically and objectively evaluated the safety of gamithromycinin injection developed by Zhongsheng Challenge Biotechnology company in Tianjin,and carried out the phase Ⅱ clinical trial of pasteurella infection in calves,which provide theoretical data for the application of batches of new veterinary drugs of Gamithromycinin.Methods: 1.Selected 24 cattle which is 4-month-old and healthy,and given 1,3,and 5 times the recommended therapeutic dose 6 mg/kg body weight for subcutaneous injection into the neck of test cattle.Before and after each dose,the blood of each group of test cattle was collected,blood routine and blood biochemical indicators were measured,and after the dose was stopped,each dose group was slaughtered and the heart,liver,spleen,lungs,and kidneys were collected.Pathological sections were made from tissues such as lymph nodes,testis and injection site for histological observation.2.According to the Guidelines for phase II clinical efficacy evaluation of antimicrobial agents from the Ministry of Agriculture,42 calves were selected for the experiment,divided into healthy control groups,and 3,6 and 12 mg/kg doses of Gamithromycin treatment groups,and Tulathromycin treatment groups.Infection of Pasteurella multocida through artificial infection,Establish a disease model,and Tulathromycin injection as a control drug,According to the clinical symptom score after treatment,to explore the therapeutic effect of different doses of Gamithromycin.Results: 1.There was no significant difference in 15 blood routine indexes such as RBC,WBC and LYM between the control group and the recommended therapeutic dose of 1,3,and 5 times of the treatment dose of Gamithromycin group(P >0.05),there were no significant differences in 21 blood biochemical indexes,such as sodium,potassium,phosphorus,calcium,magnesium ion and ALT、GLBN、TBIL between the two groups compared with the control group(P >0.05).And there were no obvious pathological changes in organs before and after administration of drugs in each experimental group.3.With the effective rate as the evaluation standard,the cure rates of the 12,6 and3 mg/kg gamithromycinin injection group and the tulathromycin control group were100%,100%,85.7% and 100%,respectively.The effective rates of the 12 and 6 mg/kg dose groups and the tulathromycin group were significantly higher than those of the infection control group(P <0.05).Conclusion: There is no obvious adverse reaction to the target animal cattle with the injection of gamithromycin The application of gamithromycin injection developed by Zhongsheng Challenge Biotechnology company in Tianjin can be safely used clinically.This medicine can effectively treat Pasteurella bovis infection.Clinical recommended dose is Use 10% gamithromycin administered once by subcutaneous injection at 6 mg/kg body weight.