Packaging and storage—
Preserve in tight containers, remote from fire, and store at controlled room temperature.
Labeling—
Label it to indicate that it is flammable.
Specific gravity 
841
:
between 0.8691 and 0.8771 at 15.56
(the U.S. Government standard temperature for alcohol determination), for Rubbing Alcohol manufactured with specially denatured alcohol Formula 23-H.
Limit of nonvolatile residue—
Where the denaturant is denatonium benzoate—
Evaporate 200.0 mL of Rubbing Alcohol, transferred in convenient portions, in a suitable tared dish on a steam bath, and dry the residue at 105
for 1 hour: the weight of the residue is not less than 2.8 mg. (Retain the residue for the
Assay for denatonium benzoate.)
Where the denaturant is sucrose octaacetate—
Evaporate 25.0 mL of Rubbing Alcohol in a suitable tared dish on a steam bath, and dry the residue at 105
for 1 hour: the weight of the residue is not less than 89 mg. (Retain the residue for the
Assay for sucrose octaacetate.)
Methanol—
Dilute 0.50 mL of it with water to 1.0 mL. To 0.50 mL of the resulting solution add 1 drop of dilute phosphoric acid (1 in 20) and 1 drop of potassium permanganate solution (1 in 20). Mix, allow to stand for 1 minute, and add sodium metabisulfite solution (1 in 20), dropwise, until the permanganate color is discharged. If a brown color remains, add 1 drop of dilute phosphoric acid (1 in 20). To the colorless solution add 5 mL of freshly prepared
chromotropic acid TS, and heat in a water bath at 60
for 10 minutes: no violet color appears.
Assay for denatonium benzoate—
Buffer solution—
Dissolve 9.23 g of anhydrous dibasic sodium phosphate in 800 mL of water, adjust with saturated citric acid solution to a pH of 4 ± 0.1, dilute with water to 1000 mL, and mix.
Assay preparation—
Dissolve the residue obtained in the test for Limit of nonvolatile residue in 50.0 mL of water, and transfer to a suitable flask.
Procedure—
Treat the
Standard preparation, Assay preparation, and blank similarly and concomitantly. Transfer 10.0 mL each of the
Standard preparation, Assay preparation, and
Buffer solution to individual 250-mL separators, and add to each 40 mL of
Buffer solution, 10 mL of a 1 in 1000 solution of bromophenol blue in chloroform, and 60 mL of chloroform. Shake the separators vigorously for 2 minutes, allow to stand for 15 minutes, then withdraw the chloroform layers through chloroform-washed cotton into 100-mL volumetric flasks. Repeat the extraction with 20 mL of chloroform, adding the filtered chloroform extracts to the respective volumetric flasks, dilute with chloroform to volume, and mix. Without delay, concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 410 nm, with a suitable spectrophotometer, using the blank to set the instrument. Calculate the quantity, in mg, of denatonium benzoate (C
28H
34N
2O
3·H
2O) in 100 mL of Rubbing Alcohol taken by the formula:
0.025C(AU / AS),
in which
C is the concentration, in µg per mL, of
USP Denatonium Benzoate RS in the
Standard preparation; and
AU and
AS are the absorbances of the solutions from the
Assay preparation and the
Standard preparation, respectively.
Assay for sucrose octaacetate—
Using about 50 mL of 70% alcohol, transfer the residue obtained in the test for
Limit of nonvolatile residue to a 500-mL conical flask. Neutralize the solution with 0.1 N sodium hydroxide VS, using
phenolphthalein TS as the indicator. Add 25.0 mL of 0.1 N sodium hydroxide, attach an air condenser to the flask, and reflux on a steam bath for 1 hour. Remove from the steam bath, cool quickly, and titrate the excess alkali with 0.1 N sulfuric acid VS, using
phenolphthalein TS as the indicator. Perform a blank determination (see
Residual Titrations under
Titrimetry 541). Each mL of 0.1 N sodium hydroxide is equivalent to 8.483 mg of sucrose octaacetate (C
28H
38O
19).
Auxiliary Information—
Staff Liaison :
Clydewyn M. Anthony, Ph.D., Scientist
Expert Committee : (MDCCA05) Monograph Development-Cough Cold and Analgesics
USP29–NF24 Page 69
Pharmacopeial Forum : Volume No. 27(3) Page 2507
Phone Number : 1-301-816-8139
