Studies were conducted on Wistar rats; pyelonephritis was modeled by the introduction of mercury dichloride and Staphylococcus aureus. To confirm the development of pyelonephritis, clinical, laboratory, hematological, and morphological changes were assessed. 

To include the antibacterial drugs into the stroma of the erythrocytes we have used the method hypoosmatic hemolysis that allows for injecting of the maximum amount of drug. For the immobilization of aminoglycosides or fluoroquinolones into leukocyte carriers we have used methods of Lokhvitskiy S.V. 

To assess the effectiveness of free and cell forms of the aminoglycosides and fluoroquinolones in experimental pyelonephritis we have used intravenous single dose of drugs calculated according to the standard technique in rats. Body temperature was measured once a day at the same time (9-10 h) till its full normalization and the next two days thereafter, the excretory renal function and body weight were determined on the 4th and the following days, laboratory parameters were determined in all groups at 5th and 10th day after the development of pyelonephritis. 

It was established that a fivefold administration of the gentamicin to the animals with pyelonephritis at a dose of 2 mg/kg, of the amikacin at a dose of 12 mg/kg, of the ciprofloxacin and ofloxacin in the dosage of 3 mg/kg has normalized the body temperature to a day 10-12, the excretory function of the kidneys to a day 12-14, while the weight of the animals was not significantly changed. On 10th day the number of leukocytes in the blood was increased by 10-12%, the number of lymphocytes was reduced by 8-9%, the number of neutrophils did not change, the imbalance of enzyme activity in the kidneys has decreased, but not normalized. 

In contrast, a single administration to rats with pyelonephritis erythrocytic or leukocytic forms of antibacterial drugs in single doses normalized the body temperature by Days 7-8 or 5-6, the excretory function of the kidney by Days 8-9 or 5-6, respectively, the weight of the animals increased slightly, by 10th day a complete normalization was seen for the leukocyte count, lymphocytes, neutrophils in the blood and activity of enzymes in the kidneys. 

Authors declare lack of the possible conflicts of interests.