Reduction of dibekacin-induced nephrotoxicity in the rat by the formation of N-alkylsulfonate derivatives.

Seven N-alkylsulfonate derivatives of an aminoglycoside antibiotic, dibekacin, were prepared and their nephrotoxicity was examined. Using water-supplied and water-depleted rats and the BUN value as a nephrotoxic measure, dibekacin-di-N-methanesulfonate, pentasodium dibekacin-penta-N-methanesulfonate, -penta-N-ethanesulfonate, disodium dibekacin-di-N-methanesulfonate sesquisulfate, disodium and dipotassium dibekacin-di-N-ethanesulfonate sesquisulfates and sodium dibekacin-mono-N-ethane-sulfonate disulfate showed low nephrotoxicity as compared to that of the original dibekacin sulfate. Notably, dibekacin-di-N-methanesulfonate caused little change in the BUN value and was bioactive in vitro but not active in vivo against a Pseudomonas aeruginosa infection model in mice. Among the bioactive N-alkylsulfonates in vivo, disodium and dipotassium dibekacin-di-N-ethanesulfonate sesquisulfates showed a lower degree of elevation of BUN, urine volume and urine protein, lower mortality and better body weight gain than those of dibekacin sulfate during consecutive treatment for 12 and 28 days.