Simultaneous Determination Of3MALs Residues And The Studies On Their Pharmacokinetic In Chicken By LC-MS/MS

The macrolide antibiotics(MALs) have salient antibacterial activity for mycoplasmaand G+bacteria, tylosin (TYL) and tilmicosin (TILM) are frequently used in veterinaryclinic as the special animal antibiotics. The concentration of azithromycin(AZI) in diseasesite is significantly higher than that of normal part, it is illegally used in veterinary clinicalbecause of its remarkable antibacterial effect. Inappropriate use of such drugs can causeveterinary drug residue, which will pose a serious hazard to human health, so it isnecessary to monitor the residue.A high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS) for the determination of there MALs (TYL, TILM, AZI) was establishedin chicken, liver, kidney and plasma. And the Pharmacokinetics of3MALs in chickenswas studied. Samples were extracted with acetonitrile and cleaned-up by MCXcartridge(Plasma samples excepted).The three antibiotics were separated with luna C8column by a gradient elution program with0.1%formic acid-acetonitrile and0.1%formicacid-water as the mobile phase. The identification of three drugs was carried out bypositive electrospray ionization(ESI+) in multiple reaction monitoring (MRM) mode. Theplasma and tissues samples were collected in different intervals after oral administration ofMALs, then detected by LC-MS/MS method. The concentration-time data of3drugs inplasma and tissues were analyzed with3P97pharmacokinetics software.The results showed that: the calibration curves had good linearity for3antibiotics inthe range of1-100ng/mL,with correlation coefficient greater than0.998. The limits ofdetection(LOD) were0.3-1.0、0.1-0.6、0.3-0.7μg/kg (ng/mL) and the limits ofquantification(LOQ) were1.0-3.0、0.3-1.5、1.0-3.0μg/kg (ng/mL) for AZI、TYL、TILMin four matrices. The average recoveries varied from83.5%-108.0%and the RSDSwere inthe range of4.3%-15.2%. The results indicated the plasma drug concentration-time dataswere two-compartment model with absorption. The absorption half-life(t1/2ka) of TYL was0.041h, the elimination half-life(t1/2β) was16.03h. The time-point of maximum plasmaconcentration(Tp) and the maximum plasma concentration(Cmax) were0.30h and131.27ng/mL. The area under the concentration-time curve(AUC) was1588.62(ng/mL)·h; Thet1/2kaof TILM was0.49h and t1/2βwas22.84h, the Tmaxwas0.73h and Cmaxwas170.91ng/mL, AUC was1079.31(ng/mL)·h; The t1/2kaand t1/2βof AZI was1.39h and30.44h,the Tp was2.46h and Cmaxwas129.37ng/mL, AUC was1922.34(ng/mL)·h. Tissuedistribution revealed that in addition to the TILM in chicken and AZI in liver belonged to absorption in one-compartment model, the remaining were absorption in two-compartmentmodel. The drugs were mainly distributed in the liver and kidney, the rate of eliminationwas TYL>TILM>AZI.