Improved Method for the Determination of Residual Aminoglycoside Antibiotics in Animal Tissues by Electrophoresis and Bioautography

The use of agar gel electrophoresis and bioautography for the identification of small amounts of seven aminoglycoside antibiotics (streptomycin, dihydrostreptomycin, kanamycin, bekanamycin, gentamicin, fradiomycin and paromomycin) was studied. The procedure used for the electrophoretic separation of these components is described. The antibiotics were detected with high sensitivity using Bacillus subtilis ATCC 6633 as a test organism, Tris buffer at pH 8.0, and Bacto-Agar as the supporting medium for each of the components. The limits of detection obtained for the various antibiotics ranged between 0.078 and 0.313 μg/ml and the standard deviation ranged from 0.05 and 0.34. Recoveries from extracts of bovine kidney tissue containing each drug ranged from 59.0% to 90.2%. The sensitivity of this method can be adjusted through minor modifications, thus allowing it to be used for routine residual analysis of aminoglycosides in biological samples.