Identification—
Place about 10mLin a suitable beaker,and adjust to a pHof about 2(pHindicator paper)using 3Nhydrochloric acid.Add up to 2g of finely powdered sodium chloride,in two portions of about 200mg each initially,and then in smaller portions (about 25mg),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 3Nhydrochloric acid,and stir until the precipitate forms.
]Allow to stand at room temperature for 15minutes,and collect the residue by suction filtration:the acetylcysteine so obtained,after being dried as directed in the test for
Loss on dryingunder
Acetylcysteine,responds to the
Identificationtest under
Acetylcysteine.
Assay—
Mobile phase,Internal standard solution,Standard preparation,and Chromatographic system—
Proceed as directed in the
Assayunder
Acetylcysteine.
Assay preparation—
Pipet a volume of Solution,equivalent to about 1000mg of acetylcysteine,into a 100-mLvolumetric flask,dilute with sodium bisulfite solution (1in 2000)to volume,and mix.Pipet 10.0mLof this solution and 10.0mLof Internal standard solutioninto a 200-mLvolumetric flask,dilute with sodium metabisulfite solution (1in 2000)to volume,and mix.
Procedure—
Proceed as directed for
Procedurein the
Assayunder
Acetylcysteine.Calculate the quantity,in mg,of C
5H
9NO
3Sin each mLof the Solution taken by the formula:
2000(C/V)(RU/RS),
in which
Cis the concentration,in mg per mL,of
USP Acetylcysteine RSin the
Standard preparation;Vis the volume,in mL,of Solution taken;and
RUand
RSare the ratios of the peak response of acetylcysteine to that of
DL-phenylalanine obtained from the
Assay preparationand the
Standard preparation,respectively.