A: Infrared Absorption 197K.

B: Ultraviolet Absorption 197U—

C: Shake a quantity of it, equivalent to 4 mg of albuterol, with 10 mL of water, and filter: the filtrate so obtained meets the requirements of the tests for Sulfate 191.

D: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.

0.05 ± 0.01 M Ammonium acetate solution— Dissolve 3.85 g of ammonium acetate in 1000 mL of water, and mix.

Mobile phase— Prepare a degassed mixture of water, 0.05 ± 0.01 M Ammonium acetate solution, and isopropanol [65: 30: (5 ± 1)], and adjust dropwise with acetic acid to a pH of 4.5 ± 0.3.

Standard preparation— Dissolve an accurately weighed quantity of USP Albuterol Sulfate RS in water, and dilute quantitatively with water to obtain a solution having a known concentration of about 0.6 mg per mL.

Assay preparation— Transfer about 60 mg of Albuterol Sulfate, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with water to volume, and mix.

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 276-nm detector and a 4.6-mm × 20-cm column that contains packing L10. The flow rate is about 2.0 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the resolution, R, between albuterol and 4-[2-[(1,1-dimethylethyl)amino]-1-hydroxyethyl]-2-methylphenol sulfate is not less than 1.5; and the relative standard deviation for replicate injections is not more than 1.5%.

Procedure— Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of (C13H21NO3)2·H2SO4 in the portion of Albuterol Sulfate taken by the formula: in which C is the concentration, in mg per mL, of USP Albuterol Sulfate RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.