Identification—
Place about 10 mL in a suitable beaker, and adjust to a pH of about 2 (pH indicator paper) using 3 N hydrochloric acid. Add up to 2 g of finely powdered sodium chloride, in two portions of about 200 mg each initially, and then in smaller portions (about 25 mg), stirring after each addition until the sodium chloride dissolves and a precipitate is formed.
[NOTE—The precipitate appears as a very fine powder, and the solution turns cloudy. If no precipitate forms, add an additional drop of 3 N hydrochloric acid, and stir until the precipitate forms.
] Allow to stand at room temperature for 15 minutes, and collect the residue by suction filtration: the acetylcysteine so obtained, after being dried as directed in the test for
Loss on drying under
Acetylcysteine, responds to the
Identification test under
Acetylcysteine.
Assay—
Mobile phase, Internal standard solution, Standard preparation, and Chromatographic system—
Proceed as directed in the
Assay under
Acetylcysteine.
Assay preparation—
Pipet a volume of Solution, equivalent to about 1000 mg of acetylcysteine, into a 100-mL volumetric flask, dilute with sodium bisulfite solution (1 in 2000) to volume, and mix. Pipet 10.0 mL of this solution and 10.0 mL of Internal standard solution into a 200-mL volumetric flask, dilute with sodium metabisulfite solution (1 in 2000) to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Acetylcysteine. Calculate the quantity, in mg, of C
5H
9NO
3S in each mL of the Solution taken by the formula:
2000(C/V)(RU / RS),
in which
C is the concentration, in mg per mL, of
USP Acetylcysteine RS in the
Standard preparation; V is the volume, in mL, of Solution taken; and
RU and
RS are the ratios of the peak response of acetylcysteine to that of
DL-phenylalanine obtained from the
Assay preparation and the
Standard preparation, respectively.
71
:
meets the requirements.