The large-scale production of antibiotics able to the targeted drug delivery to the affected tissues and target cells is relevant for ensuring an increase in the effectiveness of the humans and animals treatment. The aim of this study is to evaluate the effect of the antibiotic enrofloxacin applied alone or in combination with the nanopolymer PEG-400 on the activity of the transamination enzymes (ALT, AST) and the concentration of bilirubin in the rats’ serum. The complex enrofloxacin-PEG400 was obtained by the reaction of enrofloxacin chloride with PEG-400. Four groups of 12 rats each were studied; there were three experimental groups and a control one. Control group rats were injected intramuscularly with saline, the first experimental group with the antibiotic enrofloxacin, the second with the nanopolymer PEG-400, the third with the complex enrofloxacin-PEG-400. Seven days after the drug administration, studies showed that the antibiotic enrofloxacin, injected alone and in combination with the nanopolymer PEG-400 increases an aminotransferase activity and the total bilirubin in the rats’ blood. This may indicate the structural and functional liver strain. Fourteen days after the experiment, the lowest activity of ALT and AST, as well as a decrease in total bilirubin was founded in the blood of experimental groups of rats treated with the complex of the antibiotic enrofloxacin and the nanopolymer PEG-400. 21 days after the administration of the enrofloxacin- PEG400 complex in the rats’ blood the aminotransferase activity was corresponding to physiological values, and the bilirubin content was significantly reduced. It may prove the restoration of the structure and the functional state of liver cells.In the further research it is planned to study the effect of the enrofloxacin –nanopolymer PEG-400 complex on the functional state and the structure of other organs and systems of the body
rats, antibiotic enrofloxacin, nanopolymer, AST, ALT, bilirubin