| Tylosin is a macrolide antibiotics used for livestock and poultry diseases usually. Tylosin is extensively applied to veterinary clinic for various kinds animal disease caused by mycoplasmata and gram-positive bacteria because of its extensive antimicrobial spectrum and tiny toxic and side-effect. The wet granulation was used for Compound Tylosin Granule preparation, while the test were performed for its quality investigation, acute toxicity, the antibacterial effect in vitro and therapeutic experiment in chicken on Compound Tylosin Granule.1. The study on quality investigation for Compound Tylosin Granule The Compound Tylosin Granule has been preparated by wet granulation according to the Prescription. UV-spectrophotometer was used to survey the contents of Tylosin and baicalin in Compound Tylosin Granule, and the granularity, dry agravity, nature of dissolve were also investigated for the Compound Tylosin Granule. The average recovery of Tylosin was 95.86%, the RSD within a day was 2.5436% and the RSD between days was 2.4859%, and the average content of Tylosin was 97.7 mg/g as well. The average recovery of baicalin was 94.44%, the RSD within a day was 3.5322% and the RSD between days was 3.9546%, the average content of Baicalin was 58.2 mg/g as well. The result showed that the content, granularity, dry agravity and nature of dissolve were fitting to the request.2. The study on acute toxicity test for Compound Tylosin Granule Modified Korbor's method were used in chicken acute toxcity test on Tylosin Tartrate, Compound Tylosin Granule. The maximum tolerable dose of baicalin was also tested in chicken. The results indicated that LD50 of Tylosin to chicken by oral was 2.5972 g/kg, 95% confidence limit was 2.1518～3.1355 mg/kg, the chicken's LD50 of Compound Tylosin Granule by oral was 25.9670 g/kg, 95% confidence limit was 21.6435～31.1551 g/kg, so it could suggest that the Compound Tylosin Granule be actual nonvenomous according to toxicity classification. The result displaied that maximum tolerable dose of baicalin in chicken was 10.94 g/kg, so it was was safe in clin.3. The study on Inhibition Effect to Bacteria of Tylosin and Baicalin in Vitro The twofold broth dilution method in test tube was applied to determine the Minimal inhibitory concentration (MIC) and minimal bactericidal concentration(MBC) of tylosin, baicalin against Streptococcus, Staphylococcus aureus, Escherichia coli, Salmonella, and the fractional inhibitory concentration(FIC) index was detected with checkerboard method to judge the synergisms of the combination of tylosin tartrate and baicalin on pathogenic bacteria above. The results indicate that the MIC of tylosin against the four bacteria above were, respectively, 1μg·mL-1, 4μg·mL-1, 512μg·mL-1, 512μg·mL-1, and the MBC were, respectively, 2μg·mL-1, 4μg·mL-1, 512μg·mL-1, 1 024μg·mL-1. The MIC of baicalin against the four bacteria abov were, respectively, 0.125 mg·mL-1, 0.125 mg·mL-1, 4 mg·mL-1, 2 mg·mL-1 and the MBC were, respectively, 0.25 mg·mL-1, 0.125 mg·mL-1, 4 mg·mL-1, 4 mg·mL-1. The FIC of tylosin combined with baicalin against the four frequent bacteria was 0. 5～1. 0. The antibacterial effect of tylosin and baicalin against gram-positive bacteria was comparatively strong. The combination of tylosin and baicalin to these bacteria had additive effect.4. The study on pharmacodynamics for Compound Tylosin Granule After the chickens were infected factitially by Staphylococcus aureus, all the therapeutic groups of chickens were treated respectively with Compound Tylosin Granule(300 mg/L,500 mg/L,700 mg/L), tylosin(500 mg/L), baicalin(500 mg/L)through drinking. The results show that the mortality in middle-dosage group and the high- dosage group of Compound Tylosin Granule were notablely lower or extremely lower than that of other medication groups (P<0.05 or P<0.01). There is no significantly difference between the middle-dosage group and high-dosage group of Compound Tylosin Granule (P > 0.05). The average relative growth rate in middle-dosage group and the high-dosage group of Compound Tylosin Granule were extremely higher or significantly higher than that of other medication groups (P<0.01 or P<0.05). There is no significantly difference between the middle-dosage group and high-dosage group of Compound Tylosin Granule (P>0.05).The curative effect of the middle-dosage group and high-dosage group of Compound Tylosin Granule were better than other groups. These two dosages of Compound Tylosin Granule was no harmful influence to chickens and could be used to Cure livestock and poultry diseases caused by bacteria. |
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