Pharmacokinetics of lidocaine in serum and milk of mature Holstein cows |
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| Authors: | G SELLERS H C LIN M G RIDDELL W R RAVIS S H DURAN & M D GIVENS |
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| Institution: | Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL, USA;;Executive Vice President, American Association of Bovine Practitioners, Auburn, AL, USA;;Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, AL, USA;;Department of Pathobiology, College of Veterinary Medicine, Auburn University, AL, USA |
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| Abstract: | The purpose of this study was to evaluate the pharmacokinetics of lidocaine in mature Holstein cows following an inverted L and caudal epidural nerve block. Plasma and milk concentrations were determined using high-performance liquid chromatography assay. Pharmacokinetic parameters were estimated using a noncompartmental method. Following administration via inverted L nerve block, serum Tmax was 0.521 ± 0.226 h and serum Cmax was 572 ± 207 ng/mL. Serum AUC was 1348 ± 335 ng·h/mL. Apparent serum t½β was 4.19 ± 1.69 h and MRT was 5.13 ± 2.33 h with clearance uncorrected for the extent of absorption of 2.75 ± 0.68 L/kg/h. The last measurable time of lidocaine detection in serum was 8.5 ± 1.4 h with a mean concentration of 51 ± 30 ng/mL. Milk Tmax was detected at 1.75 ± 0.46 h with Cmax of 300 ± 139 ng/mL. Milk AUC till the last time was 1869 ± 450 ng·h/mL with the mean AUC milk to AUC serum ratio of 1.439 ± 0.374. The last measurable time of lidocaine detection in milk was 32.5 ± 16.2 h with a mean concentration of 46 ± 30 ng/mL. There was no detectable lidocaine concentration in any samples following caudal epidural administration. |
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