A: Dilute the Injection with water to obtain a solution containing 6 mg of tobramycin per mL, and proceed as directed for Identification test A under Tobramycin, beginning with “Apply 3 µL of this test solution”.

B: The retention time of the major peak for tobramycin in the chromatogram of the Derivatized assay preparation corresponds to that in the chromatogram of the Derivatized standard preparation, as obtained in the Assay.

(Official January 1, 2007)

Mobile phase, 2,4-Dinitrofluorobenzene reagent, Tris(hydroxymethyl)aminomethane reagent, Standard preparation, Derivatization procedure, Resolution solution, and Chromatographic system— Proceed as directed in the Assay under Tobramycin.

Assay preparation— Dilute an accurately measured volume of Injection quantitatively, and stepwise if necessary, with water to obtain a solution containing the equivalent of about 0.2 mg of tobramycin per mL.

Procedure— Proceed as directed in the Assay under Tobramycin. Calculate the quantity, in mg, of tobramycin (C18H37N5O9) in each mL of the Injection taken by the formula: in which L is the labeled quantity, in mg per mL, of tobramycin (C18H37N5O9) in the Injection; D is the concentration, in mg per mL, of tobramycin in the Assay preparation, on the basis of the labeled quantity, the volume taken, and the extent of dilution; and the other terms are as defined therein.