Stability of parenteral solutions of tobramycin sulfate

The stability and physical compatibility of tobramycin sulfate in commonly used intravenous fluids were evaluated; in addition, pH values were obtained on 1 mg/ml tobramycin solutions, and microbiological potencies were obtained on 1 mg/ml and 0.2 mg/ml concentrations for 24- and 48-hour periods at 25 C. Most solutions were stable for 48 hours at room temperature. However, it is recommended that solutions of tobramycin sulfate be discarded after 24 hours to minimize the potential for inadvertent introduction of microorganisms during manipulations in the hospital environment.