Determination of cloxacillin residues in dairy cows after intramammary administration |
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| Authors: | A Burmańczuk T Grabowski M Osypiuk B Polska C Kowalski |
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| Affiliation: | 1. Department of Pharmacology, Faculty of Veterinary Medicine, University of Life Sciences, Lublin, Poland;2. Polpharma Biologics, Gdańsk, Poland |
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| Abstract: | The aim of this study was to perform a comparative analysis of the characteristics of cloxacillin (CLO) (MRL of withdrawal in bovine milk is 30 ng/g) after a single intramammary (IMM) dose in the dry period (DP) and lactation (LP), and to establish a high‐performance liquid chromatography (HPLC) analytical method for CLO detection in milk. The research was conducted on a group of 10 cows in DP and 10 in LP. A single dose of 600 mg of CLO was administrated by the IMM route for a single quarter in DP and 500 mg for a single quarter in LP. CLO concentration was analyzed by HPLC. CLO was monitored at a wavelength of 206 nm. Pharmacokinetic calculations were performed using Phoenix® WinNonlin® 6.4 software. The calibration curve was linear over the range of 13.03–28 019.00 ng/g with the coefficient of determination R2 > 0.999. CLO withdrawal in both the LP and DP group had a biphasic nature. The total CLO elimination in the DP and LP group was reached after 36 and 6.5 days, respectively. A quantitative and confirmatory method for the determination of CLO in fresh milk has been established. We have confirmed that the withdrawal of CLO in the DP group is not a linear process and has a stepwise character. |
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