PHARMACOKINETICS AND BIOAVAILABILITY OF TILMICOSIN AND TIAMULIN IN BROILER CHICKEN
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Date
2022
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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 crop’, ‘in water’ and ‘in feed’ administration. Tilmicosin was administered at the dose rate of 25 mg/kg body weight through ‘in crop’ and ‘in water’ route. The dose rate for the “in feed” route was 1kg/tonne of feed. Similarly tiamulin was administered at the dose rate of 20 mg/kg body weight through ‘in crop’ and ‘in water’ route. The dose rate for ‘in feed’ route was 1 kg/tonne of feed. The important pharmacokinetic parameters following ‘in crop’ administration of tilmicosin phosphate estimated were: Cmax, 1.0 ± 0.53 μg.ml-1, AUC0-ꟹ,8.61± 6.50 μg.h.ml-1, t1/2, 6.13 ± 5.67 h; MRT, 6.06 ± 6.56 h, Vd area/F, 341.06 ± 265.25 L.kg-1, ClB/F 55.16 ± 65.52 ml.min-1.kg-1. Following ‘in water’ administration, the important pharmacokinetic parameters were: Cmax, 0.25 ± 0.06 μg.ml-1, AUC0-ꟹ, 4.73 ± 3.42 μg.h.ml-1, t1/2, 13.24± 13.01 h, MRT, 3.35 ± 0.51 h, Vd area/F, 1304.80 ± 1279.34 L.kg-1. Following ‘in feed’ administration, the important pharmacokinetic parameters were: Cmax: 1.72 ± 1.32 μg.ml-1, AUC0-ꟹ, 21.51 ± 7.42 μg.h.ml-1. t1/2, 21.45 ± 17.21 h, Vd area/F, 417.96 ± 228.24. The study leads us to conclude that the given dose rate is sufficient to attain plasma concentrations well above MICs and at the same time reduce the residue load in edible parts.