[Pharmacokinetics of an antibiotic administered in cell carriers]

Tissue distribution of erythrocyte membrane-bound gentamicin was studied in non-inbred albino rats. Gentamicin was administered to the animals intravenously in single doses of 3.3 mg/kg as a free substance of the antibiotic or in carrier erythrocytes. The gentamicin concentration was determined in serum, blood and tissues of the liver, kidneys, lungs, spleen and the skeletal muscles by fluorescence polarization immunoassay (TDx, Abbott). Encapsulation of gentamicin in erythrocytes caused changes in its pharmacokinetics: the antibiotic half-life and mean retention time appeared to be higher and the antibiotic accumulation in the liver, spleen and kidneys increased 1.7-3.0, 19-27 and 1.5 times respectively depending on the technique of the carrier erythrocytes preparation. Exposure of the erythrocytes to tannin led to an increase in the rate of the antibiotic release from the carrier erythrocytes.