Identification—
A:
The UVabsorption spectrum of the Test preparation,obtained as directed in the test for Content uniformity,exhibits maxima and minima at the same wavelengths as that of the Standard preparation,concomitantly measured.
B:
To 1Tablet contained in a 15-mLtube add 4mLof pyridine and 2mLof acetic anhydride:an immediate yellow color is produced on shaking.Then heat gently on a steam bath:a rose-pink to a deep red color develops,indicating the presence of citrate ion.
Dissolution á711ñ—
Medium:
0.02Nhydrochloric acid;1000mL.
Apparatus 1:
100rpm.
Time:
30minutes.
Procedure—
Determine the amount of tamoxifen (C
26H
29NO)dissolved from UVabsorbances at the wavelength of maximum absorbance at about 275nm of filtered portions of the solution under test,suitably diluted with
Medium,if necessary,in comparison with a Standard solution having a known concentration of
USP Tamoxifen Citrate RSin the same
Medium.
Tolerances—
Not less than 75%(Q)of the labeled amount of C26H29NOis dissolved in 30minutes.
Assay—
Mobile phase—
Prepare a methanol solution containing,in each liter,320mLof water,2mLof glacial acetic acid,and 1.08g of sodium 1-octanesulfonate.
Standard preparation—
Dissolve a suitable quantity,accurately weighed,of
USP Tamoxifen Citrate RSin
Mobile phaseto obtain a solution having a known concentration of about 200µg per mL.
Assay preparation—
Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 20mg of tamoxifen,to a stoppered,50-mLcentrifuge tube.Pipet 30mLof Mobile phaseinto the tube,and shake by mechanical means for not less than 15minutes.Centrifuge at about 1000rpm,pipet 5mLof the clear supernatant into a 25-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.
Chromatographic system (see Chromatography á621ñ)—
The liquid chromatograph is equipped with a 254-nm detector and a 4-mm ×30-cm column that contains packing L11.The flow rate is about 1.5mLper minute.Chromatograph the
Standard preparation,and record the peak areas as directed for
Procedure:the relative standard deviation for replicate injections is not more than 3.0%.
Procedure—
Separately inject equal volumes (about 25µL)of the
Assay preparationand the
Standard preparationinto the chromatograph by means of a suitable sampling valve,record the chromatograms,and measure the areas for the major peaks.Calculate the quantity,in mg,of tamoxifen (C
26H
29NO)in the portion of Tablets taken by the formula:
0.15C(371.51/563.64)(rU/rS),
in which 371.51and 563.64are the molecular weights of tamoxifen and tamoxifen citrate,respectively;
Cis the concentration,in µg per mL,of
USP Tamoxifen Citrate RSin the
Standard preparation;and
rUand
rSare the peak areas obtained from the
Assay preparationand the
Standard preparation,respectively.