PEGylation of antibiotic enrofloxacin and its effects on the state of the antioxidant system in rats

Abstract

The antibiotic enrofloxacin's molecular structure has reactive carboxyl groups used for chemical modification and obtained a PEGylated form of enrofloxacin. For this, the nanopolymer polyethylene glycol-400 (PEG-400) fragments were introduced into the molecule of enrofloxacin at the carboxyl group by converting it to the anhydride group. PEGylated enrofloxacin has good solubility in water and was stable. Effects of PEGylated enrofloxacin on the antioxidant system were studied. Four groups of rats were formed: one control and three experimental. Rats of the control group were injected intramuscularly with saline. Rats of the first experimental group were injected intramuscularly with the antibiotic enrofloxacin, rats of the second experimental group were injected intramuscularly with PEG-400, and animals of the third experimental group of rats were injected intramuscularly with the complex of the antibiotic enrofloxacin with PEG-400. The rats were injected daily for four days. Biochemical studies of rat blood on 7, 14, and 21 days after the last injection showed that the blood TBARS content increased in animals injected with the antibiotic enrofloxacin compared to the control. The administration of enrofloxacin to animals resulted in a decrease of antioxidant enzymes in the blood. When animals were injected with the PEGylated form of the antibiotic enrofloxacin, the blood concentration of TBARS was the lowest, which indicates the absence of toxic effects on the cells of the body. Simultaneously, the activities of SOD, catalase, and GP in the blood of rats treated with PEGylated enrofloxacin were stable and corresponded to the formation of lipid peroxidation products. The activity of antioxidant enzymes was the highest in rats injected with PEGylated enrofloxacin. Therefore, the intramuscular administration of the newly developed PEGylated antibiotic enrofloxacin does not cause the excessive formation of lipid peroxidation products and does not harm the body's antioxidant state.