Effects of Mastitis on Pharmacokinetics of Elimination with Milk of BenzimidazoleAnthelmintics

The current study was performed to determine the effects of mastitis on behaviour of benzimidazole anthelmintic drugs in milk. Seven Brown Swiss cows with subclinical mastitis infection in one or two udder quarters and not in the first trimester period of pregnancy were used in this study. The study was conducted in cross-over design method. Albendazole (ABZ), triclabendazole (TCBZ) and fenbendazole (FBZ) at 7. 5 mg/kg, 10 mg/kg and 7.5 mg/kg single oral doses were applied to animals with mastitis and after mastitis treatment respectively. The milk and blood samples were collected at prior to drug administration and following drug application zeroth, 8th, 16th, 24th, 36th, 48th, 72nd and 120th hours. The milk and blood samples were extracted with SPE (Solid Phase Extraction) and analysed by HPLC. Mastitis caused only the change in the behaviour of ABZ in milk. AUCmilk/AUCMplasma rates were calculated respectively as 0.96, 0.95, 0.97, 0.92, 0.91 and 0.89 for albendazolesulfoxide (ABZSO), albendazolesulfon (ABZSO2), triclabendazolesulfoxide (TCBZSO), triclabendazolesulfon (TKBZSO2), fenbendazole (FBZ) and fenbendazolesulfoxide (FBZSO) in animals without mastitis. These rates in animals with mastitis were 1.28, 1.21, 0.98, 0.93, 0.97 and 0.94 respectively. While the biological half-life of ABZSO and ABZSO2 were found as 24.01 and 20.92 hour in milk of animals with mastitis, these parameters were 17.49 and 19.77 hour in milk of animals without mastitis. The biological half-life of plasma for ABZSO, ABZSO2, TKBZSO, TKBZSO2, FBZ and FBSO were calculated as 10.55, 9.94, 24.11, 31.75, 14.68, 20.13 and 16.75 hours in healthy animals. Inflammatory diseases such as mastitis may change pharmacokinetic behaviour of some drugs in the milk.