Pharmacokinetics of tulathromycin in edible tissues of healthy and experimentally infected pigs with Actinobacillus pleuropneumoniae

Abstract

The aim of this study was the comparison of the tissue pharmacokinetics of tulathromycin in healthy pigs and pigs experimentally infected with Actinobacillus pleuropneumoniae (App). Tulathromycin was given to 24 healthy and 24 infected pigs by intramuscular injection at a single dosage of 2.5 mg kg⁻¹ body weight (b.w.). Pigs were euthanised at each group and then samples of liver, kidney, muscle, injection site and skin with fat were taken at scheduled time points. Drug concentrations were determined by LC-MS/MS. In this study, higher values of the area under the concentration–time curves (AUC) were calculated in all tissue samples taken from infected than healthy pigs. In pigs with App the AUCs of liver, kidney, muscle, skin with fat and injection site were 1111, 1973, 235, 181 and 2931 mg kg⁻¹ h, while in pigs without inflammation they were 509, 1295, 151, 111 and 1587 mg kg⁻¹ h, respectively. Maximum drug tissue concentrations (C_max) in infected animals were 2370, 6650, 2016, 666 and 83 870 µg kg⁻¹, while in healthy pigs they were 1483, 6677, 1733, 509 and 55 006 µg kg⁻¹, respectively. The eliminations half-times (T_1/2) were respectively longer in all tissue samples taken from infected animals (from 157.3 to 187.3 h) than in healthy ones (from 138.6 to 161.2 h). The tulathromycin tissue concentrations were significantly higher (p < 0.05) in all tissue samples of the infected pigs compared with the healthy animals at 360 h (from 0.0014 to 0.0280) and at 792 h (from 0.0007 to 0.0242) after drug administration. The results suggest that the tissue pharmacokinetic properties and residue depletion of tulathromycin can be influenced by the disease state of animals.

Keywords:

• tulathromycin
• pigs
• tissue pharmacokinetics
• residue depletion

Acknowledgements

The authors thank Janina Wrótniak, Marta Piątkowska and Maja Antczak for help in organising the study and for operational support.

Additional information

Funding

This work was financially supported by the Ministry of Science and Higher Education in Poland [project number NN 308575540].