Identification
Dissolve 5Tablets in 40mLof water in a 250-mLseparator.Add 3mLof sodium hydroxide solution (1in 2),and extract with two 50-mLportions of chloroform.Extract the combined chloroform extracts in a 250-mLseparator with two 15-mLportions of 0.5Nhydrochloric acid,and evaporate the combined aqueous extracts on a steam bath to dryness.Dissolve the residue in 5mLof acetone,and add 50mLof anhydrous ether to the solution.On standing,phenmetrazine hydrochloride will crystallize out.Filter the precipitate,wash with anhydrous ether,and dry at 105

:the crystals so obtained melt within a range of 3

between 172

and 182

(see
Melting Range or Temperature á741ñ).
Dissolution á711ñ
Medium:
water;900mL.
Apparatus 2:
50rpm.
Time:
45minutes.
Procedure
Determine the amount of C
11H
15NO·HCl dissolved from UVabsorbances at the wavelength of maximum absorbance at about 256nm on filtered portions of the solution under test,suitably diluted with
Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of
USP Phenmetrazine Hydrochloride RSin the same
Medium.
Tolerances
Not less than 75%(Q)of the labeled amount of C11H15NO·HCl is dissolved in 45minutes.
Assay
Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 250mg of phenmetrazine hydrochloride,to a 250-mLvolumetric flask,add about 125mLof 0.5Nhydrochloric acid,shake by mechanical means for 1hour,dilute with 0.5Nhydrochloric acid to volume,and mix.Transfer 50.0mLof the solution to a 250-mLseparator,add 5mLof sodium hydroxide solution (1in 2),and extract with four 50-mLportions of chloroform,collecting the chloroform extracts in a second 250-mLseparator.Extract the combined chloroform extracts with six 15-mLportions of 0.5Nhydrochloric acid,collecting the aqueous extracts in a 100-mLvolumetric flask,and dilute with 0.5Nhydrochloric acid to volume to obtain the
Assay preparation.Concomitantly determine the absorbances of the
Assay preparationand of a Standard solution of
USP Phenmetrazine Hydrochloride RSin the same medium,having a known concentration of about 500µg per mL,in 1-cm cells,at the wavelength of maximum absorbance at about 256nm,with a suitable spectrophotometer,using 0.5Nhydrochloric acid as the blank.Calculate the quantity,in mg,of C
11H
15NO·HCl in the portion of Tablets taken by the formula:
0.5C(AU/AS),
in which
Cis the concentration,in µg per mL,of
USP Phenmetrazine Hydrochloride RSin the Standard solution,and
AUand
ASare the absorbances from the
Assay preparationand the Standard solution,respectively.