Study On The Residues Elimination Of Altrenogest Oral Solution In Swines

Altrenogest is a synthetic steroidal progesterone that has obvious progesterone and antigona-dotropin effects and can inhibit ovulation.In the clinical practice of foreign veterinarians,altrenogest is mainly used for the estrus of sows and mare,but in domestic veterinary clinical practice,altrenogest is not widely used,only to promote the estrus of sows,to promote estrous sows,to delay the estrus of the sows and to delay the delivery time of the sows.This research established a method for the determination of altrenogest residues in edible tissues of pigs using HPLC-MS/MS to study the laws of residue depletion in porcine tissues.The residue elimination rule provides the basis for the formulation ofwithdrawal period in pig.1.Determination of altrenogest residues in altrenogest edible tissues by HPLC-MS/MSThe liver and kidney samples were hydrolyzed by P-glucosidase/arysulfatase and extracted by acetonitrile(the muscle and fat samples were extrected by actonitrile),then the extracting solution were degreased with n-hexane.After being redissolved with ethyl acetate,the supernatant was purified by 10%sodium carbonate solution.Finally,altrenogest was analyzed by HPLC-MS/MS,and was calibrated by the external method.Thermo C18 column was choicen for the separation of altrenogest,column temperature setted at 30 ?and the injection volume was 10?L,5 mM ammonium formate-acetonitrile was used as mobile phase.The results show that the standard curve is obtained with the correlation coefficients(R2=0.999)in the concention range of 1?200?gg/kg.The limit of quantification for altrenogest is 1.0?g/kg,and the limit of detection for altrenogest is 0.5?g/kg.The recoveries of altrenogest are 60%?110%at three spiked levels of 1?2?5 ?g/kg with the relative standard deviations of 11%(n=6).The established method of altrenogest in this experiment can be used for the residue analysis of altrenogest in pig tissues.2.Study on the residus elimination of altrenogest oral liquid in swinesTwenty sows were used for residue elimination test.According to the clinical recommended dose(20 mg/tou),altrenogest oral liquid were taken orally for medicine in pig,18 days,After the drug was stopped for 6 h,1 d,5 d,10 d and 18 d,four pigs were slaughtered respectively,collecting muscle,liver,kidney,fat samples.The residues of altrenogest in edible tissues of pigs were determined by the ahead method.The results showed that all tissues reached the highest drug concentration at 6 h after drug withdrawal,with the highest liver residue,with a mean residue of 259.25 ?g/kg,followed by kidney,fat,and muscle.The average residuals were 52.33?g/kg,49.22?g/kg and25.85 ?g/kg respectively;After the first day of treatment discontinuation,the average residual levels of altrenogest in liver,kidney,fat,and muscle decreased to 33.93 ?g/kg,11.27 ?g/kg,41.95 ?g/kg,and 8.95 ?g/kg,respectively.By the 5th day of withdrawal,the residual altrenogest in the liver of only one pig out of 4 pigs was higher than that of MRLs(2 ?g/kg)to 2.81?g/kg;from the other three pigs,it was from 1 the residual amount of altrenogest in the liver of pigs was higher than the limit of quantitation,and the residual amount of altrenogest in other tissues was lower than the limit of quantitation;the altrenogest residue in all tissues of pigs was stopped at the 10th day of withdrawal.The amount is below the detection limit.The results of the residue elimination test showed that the liver was the residual target tissue of altrenogest in pigs.According to the maximum residual limit standard stipulated by EMEA,the measured data of altrenogest residue in each pig's tissues obtained at the time point after stopping the drug were calculated by the software of WT1.4,and the period of taking the altrenogest in pig's liver was 8.67 days,and the period of the rest of the altrenogest in the pig's sebum could be fixed for 5 days according to the measured concentration method.According to the clinical recommended dose(20 mg/tou),altrenogest oral liquid were taken orally for medicine in pig,18 days,the WT can be tentatively into 9d.