The article presents the results of studies of the intake (oral administration), distribution and excretion of Tilmicosin Phosphate (active ingredient of the Tilmox 25%) from the body of healthy broiler chickens of the KOBB-500 cross. The rapid absorption of Tilmicosin Phosphate from the alimentary tract of the birds and its entry into the internal organs was established. The maximum content of Tilmicosin Phosphate was found in the lungs and liver. Only in 2 hours after the beginning of the Tilmox 25% solution application, which was 17.02 ± 0.24 and 12.78 ± 0.22 μg / g, its content in the kidneys after 26 hours was 8 25 ± 0.19 μg / g, pectoral and cardiac muscles after 52 hours - 6.19 ± 0.28 and 5.23 ± 0.39 μg / g, respectively. Consumption of Tilmox 25% solution by a healthy bird was not accompanied by the accumulation of Tilmicosin Phosphate (material accumulation), since its content in the internal organs and muscles of the bird did not depend on the duration of the drug use. During 96 hours of Tilmox 25% solution consumption by broiler chickens the maximum content of Tilmicosin Phosphate was detected in the lungs, which indicates its tissue tropism. The distribution of Tilmicosin Phosphate in maximum amounts to the lungs ("organ affinity" or "tissue tropism") is important when infectious agents are localization in the lungs of poultry, as well as for the treatment of patients with respiratory diseases of various etiology. The cessation of the use of Tilmox 25% was accompanied by a significant decrease in the content of its active substance, Tilmicosin Phosphate, in the organs under study. Twenty-four hours after the cessation of consumption the tilmox solution (120 hours of the experiment), the content of Tilmicosin Phosphate in the lungs was 1.9 times less, liver – 1.6 times, kidneys – 1.4 times, pectoral muscle - 1.7 times, cardiac muscle – 1.3 times less, compared with indicators on 96 hours of experiment. Five days after the cessation of feeding the tilmox solution to broiler chickens (216 hours of the experiment), the residual amounts of Tilmicosin Phosphate in the organs under study were: in the lungs – 1.20 ± 0.03 μg / g; liver – 1.01 ± 0.02; kidneys - 0.91 ± 0.03 μg / g. The lowest content of Tilmicosin Phosphate, during this period of research, was only in one of the three samples of the heart muscle – 0.02 μg / g, and it was not detected in the pectoral muscle.

Key words: Tilmox 25 %, organs, distribution, accumulation, excretion, pharmacokinetics.