Experimental determination of the pharmacokinetic properties of trimethoprim and sulfamethoxazole combination in the blood serum of broiler chickens.

A rapid, simple and highly efficient analytical method for the targeted determination of trimethoprim and sulfamethoxazole in serum samples has been developed and used to measure the pharmacokinetic curve of these medicinal substances after administration to chicken broilers. The pharmacokinetics properties of trimethoprim and sulfamethoxazole were investigated in clinically healthy broiler chickens after the single oral administration of the commercial preparation Methoxasol (Eurovet Animal Health, B.V., The Netherlands) at a dose of 0.275 ml/kg b.w. After a single dose drug administration, the chickens were sacrificed by decapitation under general anaesthesia by Isoflurin 1 000 mg/g (Vetpharma AH, Spain) and the blood was collected at precisely defined intervals: 15, 30, 45, 60, 90, 120, 180, 360 and 720 min after the administration. The serum concentrations of amoxicillin were determined using Q Exactive tandem mass spectrometer (Thermo Fisher Scientific, USA) in conjunction with liquid chromatography. The detected pharmacokinetic parameters of trimethoprim after the oral administration were C = 2.1 ± 1.0 μg/ml; T = 1.5 h; t = 0.88 h; k  0.009 3 ± 0.001 1 1/h; AUC = 2.901 ± 1.4 μg.h/ml; AUC = 2.907 ± 1.5 μg.h/ml; V  2.632 l/kg; Cl = 2.7 l/h. The pharmacokinetic parameters of sulfamethoxazole after the oral administration were C = 47.1 ± 15.3 μg/ml; T = 1 h; t = 1.92 h; k = 0.004 6 ± 0.000 3 1/h; AUC = 89.676 ± 26.9 μg.h/ml; AUC = 94.612 ± 28.4 μg.h/ml; V = 0.584 l/kg; Cl = 0.21 l/h. To the best of our knowledge, this is the first pharmacokinetic study of the combination of sulfamethoxazole and trimethoprim in broiler chickens.