A: Dissolve 5 g of ferric chloride in 50 mL of 0.1 N hydrochloric acid. Transfer 2.5 mL of this stock solution to a 100-mL volumetric flask, dilute with 0.01 N hydrochloric acid to volume, and mix. Prepare Iron reagent at the time of use. Dissolve the specimen in water, and dilute with water to obtain a solution containing about 1 mg of streptomycin per mL. To 5 mL of this solution add 2.0 mL of 1 N sodium hydroxide, and heat in a water bath for 10 minutes. Cool in ice water for 3 minutes, then add 2.0 mL of 1.2 N hydrochloric acid, and mix. Add 5 mL of Iron reagent, and mix: a violet color is produced.

B: It responds to the tests for Sulfate 191.

Mobile phase, Standard preparation, System suitability solution, and Chromatographic system— Proceed as directed in the Assay under Streptomycin Sulfate.

Assay preparation 1 (where it is represented as being in a single-dose container)— Constitute Streptomycin for Injection in a volume of water, accurately measured, corresponding to the volume of solvent specified in the labeling. Withdraw all of the withdrawable contents, using a suitable hypodermic needle and syringe, and dilute quantitatively, and stepwise if necessary, with water to obtain a solution containing about 0.025 mg of streptomycin per mL.

Assay preparation 2 (where the label states the quantity of streptomycin in a given volume of constituted solution)— Constitute Streptomycin for Injection in a volume of water, accurately measured, corresponding to the volume of solvent specified in the labeling. Dilute an accurately measured volume of the constituted solution quantitatively, and stepwise if necessary, with water to obtain a solution containing about 0.025 mg of streptomycin per mL.

Procedure— Proceed as directed in the Assay under Streptomycin Sulfate. Calculate the quantity, in mg, of streptomycin (C21H39N7O12) withdrawn from the container, or in the portion of constituted solution taken by the formula: in which L is the labeled quantity, in mg, of streptomycin (C21H39N7O12) in the container, or in the volume of constituted solution taken; D is the concentration, in mg of streptomycin per mL, of Assay preparation 1 or Assay preparation 2, based on the labeled quantity in the container, or in the volume of constituted solution taken, respectively; and the other terms are as defined therein.