Standard preparation
Dissolve an accurately weighed quantity of
USP Azatadine Maleate RSin 0.1Nhydrochloric acid,and dilute quantitatively,and stepwise if necessary,with 0.1Nhydrochloric acid to obtain a solution having a known concentration of about 0.06mg per mL.
Procedure
Separately transfer 15.0mLof the
Standard preparation,15.0mLof the
Assay preparation,and 15.0mLof 0.1Nhydrochloric acid to provide the reagent blank to three 50-mLcentrifuge tubes fitted with glass stoppers.To each centrifuge tube add 10.0mLof 1.0Nsodium hydroxide and 20mLof solvent hexane,insert the stoppers,rotate the centrifuge tubes for about 15minutes,and centrifuge until the supernatants (solvent hexane phase)are clear.With the aid of separate syringes,transfer the supernatants to separate 50-mLcentrifuge tubes fitted with glass stoppers.Rinse each syringe with 10mLof solvent hexane,and add the rinse to the aqueous phase from which the respective supernatant was removed.Insert the stoppers,rotate each tube for about 10minutes,and centrifuge.Transfer each supernatant to the respective supernatant previously collected.Pipet 15mLof 0.1Nhydrochloric acid into each centrifuge tube containing the combined supernatants,insert the stoppers,rotate each tube for about 15minutes,and centrifuge.Remove and discard the supernatants.Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 283nm,with a suitable spectrophotometer zeroed with 0.1Nhydrochloric acid,using the prepared reagent blank.Calculate the quantity,in mg,of C
20H
22N
2·2C
4H
4O
4in the portion of Tablets taken by the formula:
25C(AU/AS),
in which
Cis the concentration,in mg per mL,of
USP Azatadine Maleate RSin the
Standard preparation;and
AUand
ASare the absorbances of the solutions from the
Assay preparationand the
Standard preparation,respectively.