Dextromethorphan Hydrobromide Oral Solution
» Dextromethorphan Hydrobromide Oral Solution contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of dextromethorphan hydrobromide (C18H25NO·HBr·H2O).
Packaging and storage—
Preserve in tight, light-resistant containers.
USP Reference standards 
11
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11—
USP Dextromethorphan Hydrobromide RS 
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Identification—
A:
Transfer about 50 mL of Oral Solution to a 250-mL separator, add 20 mL of water, 5 mL of 2.5 N sodium hydroxide, and 40 mL of solvent hexane, and shake thoroughly. Remove the solvent hexane layer, and filter through anhydrous sodium sulfate into a 150-mL beaker. Repeat the solvent hexane extraction, using two 40-mL portions and collecting the extracts in the beaker after filtering. Evaporate the combined extracts at 50
under nitrogen to dryness, and dissolve the residue in, and dilute with, 10 mL of chloroform: the solution is dextrorotatory (see Optical Rotation 781). Retain the chloroform solution for Identification test B.
under nitrogen to dryness, and dissolve the residue in, and dilute with, 10 mL of chloroform: the solution is dextrorotatory (see Optical Rotation 781). Retain the chloroform solution for Identification test B.
B:
Evaporate the chloroform solution from Identification test A on a steam bath to dryness, dissolve the residue in 2 mL of 2 N sulfuric acid, and add 1 mL of a freshly prepared solution of mercuric nitrate (prepared by dissolving 700 mg of mercuric nitrate in 4 mL of water, adding 100 mg of sodium nitrate, mixing, and filtering): no red color is produced immediately, but after heating, a yellow to red color develops in about 15 minutes.
Uniformity of dosage units 905—
905—
for oral solution packaged in single-unit containers:
meets the requirements.
Deliverable volume 698—
698—
for oral solution packaged in multiple-unit containers:
meets the requirements.
Assay—
Mobile phase and Standard preparation—
Prepare as directed in the Assay under Dextromethorphan Hydrobromide.
Assay preparation—
Pipet, using a to-contain pipet, a volume of Oral Solution, equivalent to about 10 mg of dextromethorphan hydrobromide, into a 100-mL volumetric flask, dilute with water to volume, and mix.
Chromatographic system and Procedure (see Chromatography 621)—
Proceed as directed in the Assay under Dextromethorphan Hydrobromide. Calculate the quantity, in mg, of dextromethorphan hydrobromide (C18H25NO·HBr·H2O) in the volume of Oral Solution taken by the formula:
621)—
Proceed as directed in the Assay under Dextromethorphan Hydrobromide. Calculate the quantity, in mg, of dextromethorphan hydrobromide (C18H25NO·HBr·H2O) in the volume of Oral Solution taken by the formula:
(370.32 / 352.32)(100C)(rU / rS)
in which 370.32 and 352.32 are the molecular weights of dextromethorphan hydrobromide and anhydrous dextromethorphan hydrobromide, respectively; C is the concentration, in mg per mL, of USP Dextromethorphan Hydrobromide RS, on the anhydrous basis, in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Clydewyn M. Anthony, Ph.D.
Senior Scientific Liaison 1-301-816-8139 |
(SM22010) Monographs - Small Molecules 2 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 2861
Pharmacopeial Forum: Volume No. 30(1) Page 95