Preparation And Pharmacodynamics Study On Compound Tilmicosin Injection

The study was to test the compatibility of Tilmicosin phosphate and DoxycyclineHyclate and determine the best ratio of these two drugs by measuring antibacterial activity invitro. Compound Tilmicosin injection was made to observe and evaluate the processes ofprescription, the quality criteria, the stability, the safety. This study will provide the scientificevidence and lay the foundation on the application of this injection in clinic.1. Preparation of Tilmicosin injection and quality controlWe determined the best ratio of Tilmicosin and Doxycycline as4:1by measuring theantibacterial effect of this injection on Pasteurella multocida, Streptococcus agalactiae,Staphylococcus aureus, Salmonella typhi, Escherichia coli in vitro respectively. Injectionwater and propylene glycol were used as main solvents, the appropriate amount of co-solvantsand antioxidants were added to make a preparation of the timicolsin injection according to theprocess of drug development. pH of Tilmicosin injection is4.0-4.2, there is no impurity byexamine clarity, which meets the requirement of injection by testing quality.2. Establishment of methods of content analysisThe concentration of Tilmicosin phosphate and Doxycycline Hyclate were measured inCompound Timicosin injection at291nm and269nm respectively, the analysis methods forrecovery, repeatability, and precision are qualified, which provides a accurate, convenient,reliable method of analyzing concentration of tilmicosin and doxycycline and observingstability of these content.3. Stability testThe results shows that the content of tilmicosin and doxycycline were decreased3.69%and4.72%respectively in strong light test although the content of them did not change inhigh temperature and low temperature test. However, the content of them were decreased2.74%and4.6%respectively in6months acceleration test.4. Safely testTo evaluate the safety of compound tilmicosin injection, the acute toxicity test, irritationtest, Pyrogen test were employed. The results show that LD50of this injection is103.17mg/kg for mice, there is little slightly irritation for injection sites, pyrogen test meets the relatedrequirements and practice.