Studies were made on tobramycin, a new broad spectrum aminoglycoside antibiotic developed by Eli Lilly Laboratories and Company. The results obtained were as follows :
1) The MIC of tobramycin against 31 strains of Staphylococcus aureus isolated from human infection foci were between 0.1 and 3.1 μg/ml, and those against Pseudomonas aeruginosa were between 0.2 and 25 μg/ml.
2) The peak level of 6.0-15.0 μg/ml was obtained in the sera of human adult volunteers at 15 to 30 minutes after single intramuscular injection of 1.5 mg/kg of tobramycin. The average urinary recovery rate of the drug was 97.4% in eight hours after the administration.
3) Distribution of the drug into rat organs : The highest tissue concentration of the antibiotic was found in kidney, followed by serum, lung, spleen and liver. This distribution pattern is similar to those found with other aminoglycoside antibiotics.
4) Distribution into rabbit bile : Concentration of the durg in rabbit bile after intramuscular injection was low (biliary recovery : 0.43-0.95%) similarly to other aminoglycoside antibiotics.
5) Ten clinical cases (each one case of bronchopneumonia and sepsis, 6 cases of urinary tract infection and 2 cases of decubitis) were treated with intramuscular injections of tobramycin (80-240 mg daily), which was effective in nine cases, except for one case of pneumonia.
