| Tilmicosin is a macrolide antibiotics for livestock and poultry,and has very superior antimicrobial activity,low drug-resistance,and wide antibacterial spectrum.The survive of various pathogenic microorganism,such as mycoplasma,Gram-positive bacteria,Gram-negative bacteria,helix,and so on,can be inhibited effectively by tilmicosin which was used for curing infectious disease of goat,cow,pig,and poultry.However,the clinical using of tilmicosin is restricted to some extent because of its poor solubility in water and bitter.As a chronic diseases,the disease of mycoplasma pneumonia caused by mycoplasma pneumoniae often happens,but results in low mortality rate.The clinical symptoms of mentioned disease include mainly chronic cough and pant.Once secondary infection of other pathogen,diseased animals show fever,loss of appetite,dyspnea,and exhaustion.The disease can infect each other among pigs in the same sty,which result in the decrease of daily weight gain,the increase of death rate,the low feed conversion and the increase of medical fee,and finally a big enconomic loss.In order to adapt market demand and make clinical use convenient,the chemical structure of tilmicosin was modified as tilmicosin phosphate by adding a phosphate group so that the solubility in water was improved obviously.The study was conducted for objectively evaluate the cure effect in vitro and in vivo,the characteristic of safety pharmacology,and the safety for target animal pig of the tilmicosin phosphate and its preparation,10%tilmicosin phosphate.To evaluate the antibacterial activity of tilmicosin phosphate,tilmicosin,tylosin,and tiarnulin in vitro,micro dilution method by doubling dilution in 96 wells plate was used to test the minimal inhibitory concentration(MIC)on 9 kinds of pathogenic bacteria.The results illustrated that the MIC of tilmicosin phosphate on Mycoplasma hyopneumoniae and Mycoplasma gallisepticum are 0.3125 and 0.0049 μg/mL,respectively,and on other pathogenic bacteria such as Actinobacillus pleuropneumoniae,Streptococcus suis,Haemophilus parasuis is between 0.0049-2.5 μg/mL.The antibacterial activity of tilmicosin phosphate was very excellent for the tested pathogenic bacteria of domestic animals.The antibacterial effect of tilmicosin phosphate is more stronger or nearly equal than that of other tested antibiotics.Compared to timicosin,tilmicosin phosphate was more soluble in the water,and then more convenient for clinical using.Accordingly,the antibacterial effect of tilmicosin phosphate on tested bacteria(mycoplasma Gram-positive bacteria,and Grain-negative bacteria)is fine,and better on partial bacteria than tilmicosin,so that tilmicosin phosphate can be administrated clinically to treat the diseases caused from the above sensitive organism mentioned.To evaluate the therapeutic effect of tilmicosin phosphate on swine mycoplasma disease,after the model of swine mycoplasma pneumonia disease was established by artificial infection,the treatment effects of different dosages of tilmicosin 10%phosphate soluble powder(10 g/0.1 kg)on mycoplasma hyopneumoniae infected piglets was evaluated by the measure of indexes such as the mortality rate,cure rate,efficiency,weight gain,pulmonary lesion score of tested piglets.The results showed that although higher dosages of 10%tilmicosin phosphate soluble powder had showed much better treatment effects on mycoplasma pneumonia disease,the therapeutic effects of 10%tilmicosin phosphate soluble powder were observed obviously already at 60-80 mg/L of dosage through drinking water,and compared with the market saling tilmicosin soluble powder(10 g/0.1 kg),were the same as that of tilmicosin soluble powder(10 g/0.1 kg,75 mg/L in water,according to tilmicosin quantity)。Meanwhile,10%tilmicosin phosphate soluble powder could remitted the reduction of weight gaining of diseased piglets.The results indicated that the dosage of 60-80 mg/L of 10%tilmicosin phosphate soluble powder should be selected as the recommended dosage to treat swine mycoplasmal pneumonia.And the water solubility of tilmicosin is significantly increased due to adding phosphate group so that it will be more convenient for tilmicosin phosphate to be clinically used in the future.In order to further evaluate the treatment effect,using dosage,and treatment time of 10%Tilmicosin Phosphate soluble powder on mycoplasma pneumonia disease in swine,on the basis of building model of mycoplasma pneumonia disease in swine,The II phages clinical study of 10%Tilmicosin Phosphate soluble powder was conducted through detecting indexes,such as death rate,cure rate,efficiency,the score of lung lesion,and physiological,biochemical and urine routine.The results showed that the dosage group of 100 mg/L、80 mg/L、60 mg/L of 10%Tilmicosin Phosphate soluble powder could induce fine therapeutic effect on mycoplasma pneumonia disease in swine,obviously reduced the scores of lung lesions in diseased piglets,and the treatment effect was equal to that 10%tilmicosin soluble powder.The administration of 10%Tilmicosin Phosphate soluble powder could also improve the weight gain of tested animals.The treatment with the dosage of 100-60 mg/L of 10%Tilmicosin Phosphate soluble powder in swine would not influence the blood routine,blood biochemical index and urine routine,and namely was safe.In conclusion,The clinical administration of 10%Tilmicosin Phosphate soluble powder was effective and safe to treat mycoplasma pneumonia disease in swine.After therapeutic test in the lab and II phages clinical study,the III phages clinical study was conducted to test the treatment effect of 10%tilmicosin phosphate soluble powder on naturally infected mycoplasma pneumonia disease in swine,and then supply a reference for clinical using.On the basis of building model of mycoplasma pneumonia disease in swine,the III phages clinical study was conducted through the detection of death rate,cure rate,efficiency,and the score of lung lesion.The results showed that the treatment effect wih 80 mg/L 10%tilmicosin Phosphate soluble powder was better than those with 60 mg/L 10%tilmicosin Phosphate soluble powder and 75 mg/L 10%tilmicosin soluble powder,but the effects in the three mentioned groups were close.The oral administration with 60～80 mg/L 10%timicosin phosphate soluble powder for one week could obviously improve the growth rate,and the effect was better than that tilmicosin with the same dosage.60～80 mg/L 10%tilmicosin phosphate soluble powder and 75 mg/L 10%tilmicosin soluble powder could obviously reduce the scores of lung lesions in diseased piglets.Therefore,the treatment effect with 60-80 mg/L tilmicosin phosphate soluble powder for mycoplasma pneumonia disease in swine was obvious,and dosage-dependent.The effect of 10%tilmicosin phosphate soluble powder on the cardiovascular system and respiratory system of domestic dogs,mouse nervous system,and the digestive system and urinary system of rat were investigated in the present study.The research showed that in the period of 180 min after drug administration through the duodenum,blood pressure,breathing rate,respiratory amplitude and electrocardiogram in the tested dogs were not influenced by 40 mg/kg、20 mg/kg and 10 mg/kg of 10%tilmicosin phosphate soluble powder and distilled water(negative control),which illustrated the tested drug was safe for cardiovascular system and respiratory system of dogs.The experimental results of 10%tilmicosin phosphate soluble powder on mouse nervous system showed that mouse auricular and the color of tail were not affected by the gavage of 240 mg/kg、120 mg/kg and 60 mg/kg of 10%tilmicosin phosphate soluble powder and distilled water(negative control).The mouse behavior was normal.Function coordination was not impacted obviously by the drug.All tested groups of 10%tilmicosin phosphate soluble powder did not show synergistic effect with pentobarbital at the subthreshold dose,and not influence the autonomic activity of mouse(P>0.05).The research results of 10%tilmicosin phosphate soluble powder on rat digestive system and urinary system showed that 120 mg/kg、60 mg/kg and 30 mg/kg of the tested drug and distilled water(negative control)by the gavage would not change the normal function of bile secretion,intestinal propulsion,gastric secretion,urine routine,blood biochemical index related to urinary system,except for the increase(within the normal range)of serum total protein and albumin in high dose group and urea nitrogen in middle dose group.To evaluate safety of tilmicosin phosphate in the clinical use on the target animal swine,fifty 40-days old Jiang Qu Hai piglets were selected and administrated tilmicosin phosphate continuously with one fold dose,three fold dose,five fold dose and ten fold dose in drinking water for 21 days.The parameters of experimental piglets,such as blood routine,blood biochemistry,blood coagulation,urine routine,feed gain ratio and histopathological observation were tested before and after the experiment.The results showed that there is no obvious clinic symptom in experimental piglets.Expect for the serum calcium and serum creatine kinase in the piglets of the ten fold dose group(800 mg/L),the tested parameters did not display the obvious differences compared with control group,indicating that tilmicosin phosphate is low toxic and it is safe to be administrated even with the ten fold dose(800 mg/L)on the target animal swine.According to the present study,we found that the survive of various pathogenic microorganism,such as mycoplasma,Gram-positive bacteria and Gram-negative bacteria could be inhibited effectively by tilmicosin phosphate.The disease of Mycoplasma pneumoniae acquired by artificial and natural infection could be cured well by the preparation,10%tilmicosin phosphate soluble powder of 60-80 mg/L water,which was advised as the recommended dosage.Meanwhile,the study also showed that,administrated with tested dosage of tilmicosin phosphate,no toxic effect was displayed in the cardiovascular system and respiratory system,nervous system,and the digestive system and urinary system of experimental animals.And 10%tilmicosin phosphate soluble powder under the 10 folds recommended dosage was safe for the physiological function of target pig.This study supplied a fine experimental basic for the clinical application of tilmicosin phosphate and its preparation,10%tilmicosin phosphate soluble powder. |
PDF Full Text Request