Pharmacokinetics and bioavailability of tilmicosin and tiamulin in broiler chicken

Abstract

The present study was taken up to develop and validate a simple and accurate method for the quantification of tilmicosin and tiamulin in poultry and to compute the dosage regimen in broiler chicken. Chromatographic separation of tilmicosin was achieved using a HPLC assay method with a C18 reverse phase column, a mobile phase consisting of ammonium formate: acetonitrile: methanol (60:30:10 v/v) pH adjusted to 5 with trifluoroacetic acid and a flow rate of 1 mL/min. For Tiamulin, the mobile phase consisted of 40mM KH2PO4 and acetonitrile in the ratio of 65:35 (pH adjusted to 2.8 with the help of orthophosphoric acid) Both the methods are simple, sensitive and reproducible. It will be useful for pharmacokinetic and tissue residue studies in pharmacology and food safety laboratories. The pharmacokinetics and bioavailability of Tilmicosin and Tiamulin were studied following in cropand#8223;, in waterand#8223; and in feedand#8223; administration. Tilmicosin was administered at the dose rate of 25 mg/kg body weight through in cropand#8223; and in waterand#8223; route. newlineThe important pharmacokinetic parameters following in cropand#8223; administration of tiamulin hydrogen fumarate estimated were: Cmax: 0.37 ± 0.04, and#956;g.ml-1, AUC0-and#43001;, 7.32 ± 1.89 and#956;g.h.ml-1, t1/2 16.91 ± 11.54 h, ClB/F, 5.76 ± 1.96 ml.min-1.kg-1, Vd/F, 124.24 ± 48.02 L.kg-1. Following in feedand#8223; administration, the important pharmacokinetic parameters were: Cmax: 0.96 ± 0.69 and#956;g.ml-1, AUC0-and#43001;, 10.16 ± 5.46 and#956;g.h.ml-1, t1/2, 7.1 ± 4.79 h. Detectible levels of plasma concentrations could not be found in the in waterand#8223; group. Only two birds showed adequate plasma concentrations of tiamulin in the in cropand#8223; group making the finding irrelevant from a statistical point of view. From this study, it can be concluded that the dose rate is not sufficient to attain therapeutic success.