Preparation And Pharmacodynamics Study On Compound Enrofloxacin Solution

Objective: In this paper, Compound Enrofloxacin Solution was made to investigate the quality criteria, stability, antibacterial activity in vitro and safety using the compatibility of Enrofloxacin(ENR) and Trimethoprim Lactate(TMP) with the optimum ratio of these two drugs by measuring in vitro antibacterial activity. This study will accumulate the data for subsequent clinical application of the drug and provide the scientific basis.Method:(1) Preparation of Compound Enrofloxacin Solution and quality control: The optimum proportion of ENR and TMP was determined by measuring the antibacterial effection of this solution on Pasteurella multocida, Streptococcus agalactiae, Staphylococcus aureus and Escherichia coli in vitro, respectively;(2) Quality Evaluation: The concentration of ENR and TMP in Compound Enrofloxacin Solution were calculated by K-ratio method and the stability of this Solution was investigated;(3) Experiment for Bacteriostasis in vitro: The effect of using two drugs in combination was investigated using FIC, measured by tube broth dilution method of combined with two drugs against four kinds of bacteria;(4) Safety Evaluation: The mice oral toxicity of LD50 of this solution was determined by acute toxicity test.Results:(1) Preparation and quality control: The optimum proportion of ENR and TMP was 2:1; Distilled water was used as main solvent, adding the appropriate amount of co-solvants and antioxidants to make a final product according to the technological process of drug development. Clarity examination of the preparation is no visible foreign matters and pH 5.0- 5.2 by testing quality, in line with the requirements of the solution.(2) Quality Evaluation: The method of drug content determination was established. The absorbance was determined at 286 nm and 329 nm. The linear relation of ENR and TMP was good, ranging from 5-20 μg/mL and 2.5-10 μg/mL, respectively; The solution was investigated by light irradiation test, high and low temperature test and accelerated tests. The results suggested the content of ENR and TMP were reduced by 7.59% and 4.83% in light irradiation test, and reduced by 5.67% and 1.40% in high temperature test, no change in low temperature test, while were reduced by 5.41% and 4.40% in accelerated test, respectively.(3) Experiment for Bacteriostasis in vitro: the combination of ENR and TMP has a synergistic effect on Pasteurella multocida and Staphylococcus aureus, while an additive effect on Rathogenic Egcherichra coil and Streptococcus agalactiae.(4) Safety Evaluation: The mice oral toxicity of LD50 of this solution was 1301.33 mg/kg for miceConclusion: Preparation of Compound Enrofloxacin Solution and establishment the method of drug content determination; Quality Evaluation in line with the requirements of the solution; Experiment for Bacteriostasis in vitro suggested the combination of ENR and TMP had positive effects; The trail of LD50 showed this solution belonged to low toxic drugs.