Distribution of gentamicin and amikacin in rabbit tissues

Rabbits were injected intramuscularly with gentamicin and amikacin (15 mg of base per kg), and the antibiotic levels in tissues were determined 20 h after either a single or multiple injections. Disk diffusion assays, with Bacillus subtilis ATCC 6633, were carried out both on homogenates and on supernatants deproteinized with trichloroacetic acid. Both assays indicated that the kidney is the major site of antibiotic deposition. Antibiotic levels increased after multiple doses. Gentamicin levels in other tissues were higher than those of amikacin. The assay of trichloroacetic acid-treated material was more sensitive than the assay of the total homogenate.