Identification
Dilute a volume of Syrup,equivalent to about 20mg of hydroxyzine hydrochloride,with 50mLof methanol,and mix.Apply 100µLof this solution and 100µLof a solution in the same medium containing about 350µg of
USP Hydroxyzine Hydrochloride RSper mLto a suitable thin-layer chromatographic plate (see
Chromatography á621ñ),coated with a 0.25-mm layer of chromatographic silica gel and dried in air for 30minutes followed by drying in vacuum at 140

for 30minutes.Allow the spots to dry,and develop the chromatogram in a solvent system consisting of a mixture of toluene,alcohol,and ammonium hydroxide (150:95:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate.Locate the spots by lightly spraying with potassium iodoplatinate TS:the
RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Assay
Standard preparation
Dissolve a suitable quantity of
USP Hydroxyzine Hydrochloride RS,accurately weighed,in water to obtain a solution having a known concentration of about 100µg per mL.
Assay preparation
Transfer an accurately measured volume of Syrup,equivalent to about 20mg of hydroxyzine hydrochloride,to a 200-mLvolumetric flask,dilute with water to volume,mix,and pass a portion through a polytef membrane filter having a 5-µm or finer porosity.
Procedure
Proceed as directed for
Procedurein the
Assayunder
Hydroxyzine Hydrochloride Tablets.Calculate the quantity,in mg,of hydroxyzine hydrochloride (C
21H
27ClN
2O
2·2HCl)in each mLof the Syrup taken by the formula:
0.2(C/V)(rU/rS),
in which
Cis the concentration,in µg per mL,of
USP Hydroxyzine Hydrochloride RSin the
Standard preparation;Vis the volume,in mL,of Syrup taken;and
rUand
rSare the peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.