Studies on the nephrotoxicity of aminoglycoside antibiotics and protection from these effects. (5). Interaction of tobramycin with latamoxef in vitro.

Interaction of tobramycin (TOB) with latamoxef (LMOX) was studied in vitro. Solutions containing TOB alone, LMOX alone or both of these compounds in varying molar ratios (TOB:LMOX = 1:1, 1:2, 1:4 and 2:1) were incubated at 37 degrees C for 0.5, 1, 3 and 5 h after adjusting to pH 7.4. Aliquots sampled at a suitable time were subjected to paper electrophoresis (PE) and thin layer chromatography (TLC). In PE, the spots of TOB and LMOX were observed as single spots on the cathode and anode sides, respectively. However, the spot associated with TOB overlapped with that associated with LMOX on the cathode side when aliquots of the solution containing both TOB and LMOX were analyzed. It seemed that the degree of overlapping became stronger with an increase in incubation time, and there were no spots corresponding to TOB alone in the mixture of TOB-LMOX (1:4). TLC analysis showed that the spot of LMOX radiated fluorescence with Rf value 0.38. On the other hand, in the mixtures, there was a definite decrease in fluorescence of LMOX at the position of Rf value 0.38, compared with that of LMOX alone. Furthermore, the spot associated with LMOX, which overlapped with that associated with TOB, also appeared at the origin on the TLC plate. The ultraviolet spectrum of the mixture of TOB-LMOX (1:2) showed a decrease in the intensity of absorption of LMOX at 268 nm. These interactions between TOB and LMOX were also observed in rat serum and its filtrate in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)