Identification—
Place about 50mLof Oral Solution in a separator,add 25mLof sodium bicarbonate solution (2in 100),and extract with three 15-mLportions of isooctane.Wash the combined isooctane extracts with 15mLof sodium bicarbonate solution (2in 100),and discard the washing.Evaporate the isooctane solution on a steam bath to dryness,and dissolve the residue in 1mLof carbon disulfide,filtering if necessary.Determine the IRabsorption spectrum as directed under
Identification—Organic Nitrogenous Bases á181ñ,obtaining the spectrum of
USP Cyproheptadine Hydrochloride RSas directed:the Oral Solution meets the requirements of the test.
Assay—
Standard preparation—
Dissolve an accurately weighed quantity of
USP Cyproheptadine Hydrochloride RSin
Mobile phaseto obtain a solution having a known concentration of about 0.02mg per mL.
Assay preparation—
Transfer an accurately measured volume of Oral Solution,equivalent to about 2mg of cyproheptadine hydrochloride,to a 100-mLvolumetric flask.Dilute with Mobile phaseto volume,and mix.Pass the solution through a filter having a 0.45-µm or finer porosity.
Procedure—
Separately inject equal volumes (about 10µL)of the
Standard preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of cyproheptadine hydrochloride (C
21H
21N·HCl)in the portion of Oral Solution taken by the formula:
100C(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Cyproheptadine Hydrochloride RSin the
Standard preparation;and
rUand
rSare the cyproheptadine peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.