Preliminary Studies On The Residue And Elimination Of Nitazoxanide In Goat Tissues

Nitazoxanide is a nitrothiazole benzamide compound that has a wide range of antimicrobial activity against parasites, bacterial and viral pathogens.Tizoxanide is detected as target substance. A determination method of nitazoxanide residue in goat tissues by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and then elimination of nitazoxanide residues in goat tissues was studied.1Determination of tizoxanide and its standard solution by HPLCWe determined the content of tizoxanide and stability of its standard solution by HPLC. We determined the maximum ultraviolet absorbance wavelength of tizoxanide by UV and purity of tizoxanide and its standard solution with area normalization method.The maximum wavelength of tizoxanide were set at360nm. The content of tizoxanide is99.14%,the within-day coefficient of variation of4μg/mL tizoxanide standard solution was0.87%and the between-day is2.86%. Standard solution of tizoxanide was stable when they were set in refrigerator for3months. The method was smiple and sensitive,which can be used to determine the content of tizoxanide and stability of its standard solution.2Determination method of nitazoxanide residue in goat tissuesThe main metabolism of nitazoxanide is tizoxanide.Which is detected as target substance. A sensitive and specific method for the determination of nitazoxanide residue in goat tissues by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed.Tissue samples were extracted with acetonitrile, the extracts were dried by nitrogen gas, redissolved in acetonitrile, filtered through0.22μm micropore film and directly injected into the LC-MS/MS system. In five tissues, the relative recovery is in the range of82.75%～100.68%.Tizoxanide in the liver samples,the calibration curves were linear(r2>0.99)in the range of0.25～25μg/kg. In liver, the intra-day coefficient of variance≤12.06%,the inter-day coefficient of variance<13.57%,limit of detection (LOD)and limit of quantitation(LOQ)were0.1μg/kg and0.25μg/kg.In kidney,muscle,fat and lung samples,the calibration curves were linear(r2>0.99)in the range of0.1～25μg/kg.In kidney, the intra-day coefficient of variances10.81%, the inter-day coefficient of variance≤10.89%, limit of detection and limit of quantitation separately were0.05μg/kg,0.1μg/kg. In muscle, the intra-day coefficient of variance≤7.18%, the inter-day coefficient of variance<9.68%.In fat, the intra-day coefficient of variance<6.44%,the inter-day coefficient of variance <10.44%. In lung, the intra-day coefficient of variance≤11.11%,the inter-day coefficient of variance≤10.47%.In muscle, fat and lung, limit of detection and limit of quantitation separately were0.025μg/kg and0.05μg/kg.The method was smiple,sensitive, high and stable recovery,which can be used to determine nitazoxanide residues in goat tissues.3Studies on the elimination of nitazoxanide in goat tissuesTizoxanide is detected as target substance, a determination method of tizoxanide residue in goat tissues by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed,elimination of nitazoxanide residues in goat tissues was studied.After administration100mg/kg oral gavage doses of nitazoxanide, the goats were slaughtered on1,3,5,7,10day and tissues were collected.Residues of nitazoxanide in goat tissues were determined by the LC-MS/MS method above.On1day, the concentrations of tizoxanide in goat tissues were18.72μg/kg,then the concentration decreased gradually,tizoxanide were also detected on10day,the concentration was in the range of0.15μg/kg～0.54μg/kg. Furthermore,the distribution of tizoxanide in goat tissues was extensive,residue of tizoxanide in liver was highest and in kidney,lung and fat less than in liver,residue of tizoxanide in muscle was the least.The velocity of elimination of tizoxanide was fast before first3days. From5days to10days, the elimination of tizoxanide in tissues was slow.The studies on the elimination of tizoxanide in goat tissues checked the above method for the determination of tizoxanide, which can be used to instruct establish of withdrawal time in goat tissues.