Studies On The Screening Of Candidate Drugs For Anti-Helicobacter Pylori And Its Quality

Helicobacter pylori is the main cause of gastritis,peptic ulcer,gastric mucosa-associated lymphoid tissue lymphoma and gastric cancer.The World Health Organization classified Helicobacter pylori as a group I carcinogen responsible for its leading role in the development of gastric cancer.At present,the clinical drugs have more side effects and poor patient compliance.With the severe situation of drug resistance,the eradication rate declines year by year.Therefore,research of safer and more effective anti-Helicobacter pylori new drugs is significant.The best candidate drugs for anti-Helicobacter pylori have been screened and its quality researches have been investigated.The main research results are as follow.1.The best candidate drug for anti-Helicobacter pylori was 2-hexyl-3-methyl-6-hydroxyquinoloneStandard bacterial strains ATCC43504、ATCC700392、ATCC700824 and clinical isolate strain S-2 as target bacterias.13 candidate drugs were screened by bacteriostatic activity in vitro.The best candidate drugs were 2-hexyl-3-methyl-6-hydroxyquinolone,of which the activity was close to amoxicillin.2.The physicochemical properties of 2-hexyl-3-methyl-6-hydroxyquinolone werestudied.The appearance of 2-hexyl-3-methyl-6-hydroxyquinolone was white powder solid,the melting point was higher than 300℃,it was slightly humidity-inducing and needed to be dried and preserved,the refractive index range was from 1.3438 to 1.3442 at 20.4℃,the oil-water partition coefficient was LgP≈3.38,it was sparingly soluble in methanol,ethanol and slightly soluble in acetonitrile,ethyl acetate,trichloromethane and DMSO.It is very slightlysolubleinwaterandpetroleumether.Theidentificationof2-hexyl-3-methyl-6-hydroxyquinolone samples confirms that the ultraviolet spectrum is consistent with the standard product and the retention time of the HPLC is the same with standard product.3.The HPLC method of 2-hexyl-3-methyl-6-hydroxyquinolone related substance were establishedchromatogram condition:Welchrom Ultimate XP-Phenyl（4.6?250 mm,5?m）,determine wavelength was 237nm,mobile phase was acetonitrile-water（45:55）,column temperature is 40℃,flow rate was 1 mL/min,injection volume 10μL.Impurity A showed a good linear between2.563?41.007?g/mL（R²=0.9992）,and the regression equation is y=28.719x-18.007.Impurity B showed a good linear between 2.578?41.251?g/mL（R²=0.9995）,and the regression equation is y=50.2x-11.03s.Impurity C showed a good linear between 2.528?40.450?g/mL（R²=0.9996）,and the regression equation is y=51.11x-11.816.Impurity D showed a good linear between 2.505?40.080?g/mL（R²=0.9994）,and the regression equation is y=48.528x-18.035.The methodological investigation shows that the method has good specificity,precision and accuracy,and is reliable.TheimpurityDwasdeterminedastherelatedsubstanceof2-hexyl-3-methyl-6-hydroxyquinolone.The result of content determination was about3.31%4.The HPLC method of 2-hexyl-3-methyl-6-hydroxyquinolone content determination were establishedchromatogram condition:Welchrom Ultimate XP-Phenyl（4.6?250 mm,5?m）,determine wavelength was 237nm,mobile phase was acetonitrile-water（45:55）,column temperature is 40℃,flow rate was 1 mL/min,injection concentration was 0.1mg/mL,injection volume 10μL.2-hexyl-3-methyl-6-hydroxyquinolone showed a good linear between 0.063?1.003 mg/mL（R²=0.9997）,and the regression equation is y=57504x-521.08.The methodological investigation shows that the method has good specificity,precision and accuracy.The result of content determination of three batches of2-hexyl-3-methyl-6-hydroxyquinolone samples was about 96.67%.5.The GC method of 2-hexyl-3-methyl-6-hydroxyquinolone residual solvent were establishedchromatogram condition:capillary column PX20（φ0.32mm×30m×1μm）,the starting column temperature is 40℃,lasts for 5minutes,rise the temperature to 130℃at 8℃per minute,lasts for 10 minutes,carrier gas is N_2,flow rate was 3.5 mL/min,inlet temperature is200℃,detector temperature is 250℃,split ratio5∶1,direct injection 0.2μL.Methanol showed a good linear between 30.120⁰.048 mg/mL（R²=0.9988）,and the regression equation is y=7524.8x-1026.Ethanol showed a good linear between 50.090⁰.080mg/mL（R²=0.9984）,and the regression equation is y=5180.6x-3004.7.Ethyl acetate showed a good linear between 50.030⁰.080 mg/mL（R²=0.996）,and the regression equation is y=9731.8x-8541.Dichloromethane showed a good linear between 6.010⁰.010 mg/mL（R²=0.9987）,and the regression equation is y=3077.1x+13.105.Trichloromethane showed a good linear between6.007⁰.010 mg/mL（R²=0.9986）,and the regression equation is y=2529.7x+26.178.Tetrahydrofuran showed a good linear between7.205⁰.012 mg/mL（R²=0.9987）,and the regression equation is y=12505x+533.95.The methodological investigation shows that the method has good specificity,repeatability and accuracy.2-hexyl-3-methyl-6-hydroxyquinolone samples weren’t detected by methanol,ethanol,ethyl acetate,dichloromethane,trichloromethane and tetrahydrofuran.6.The detection of 2-hexyl-3-methyl-6-hydroxyquinolone has been completed.The results of chloride detection were less than 0.004%;The results of sulphate test were less than 0.008%;The results of arsenic salt test were less than 0.0001%;The results of burning residue were less than 0.2%;The results of heavy metal test were less than0.001%;The results of drying weight loss were less than 0.5%.