Standard preparation—
Dissolve an accurately weighed quantity of
USP Azatadine Maleate RS in 0.1 N hydrochloric acid, and dilute quantitatively, and stepwise if necessary, with 0.1 N hydrochloric acid to obtain a solution having a known concentration of about 0.06 mg per mL.
Procedure—
Separately transfer 15.0 mL of the
Standard preparation, 15.0 mL of the
Assay preparation, and 15.0 mL of 0.1 N hydrochloric acid to provide the reagent blank to three 50-mL centrifuge tubes fitted with glass stoppers. To each centrifuge tube add 10.0 mL of 1.0 N sodium hydroxide and 20 mL of solvent hexane, insert the stoppers, rotate the centrifuge tubes for about 15 minutes, and centrifuge until the supernatants (solvent hexane phase) are clear. With the aid of separate syringes, transfer the supernatants to separate 50-mL centrifuge tubes fitted with glass stoppers. Rinse each syringe with 10 mL of 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 10 minutes, and centrifuge. Transfer each supernatant to the respective supernatant previously collected. Pipet 15 mL of 0.1 N hydrochloric acid into each centrifuge tube containing the combined supernatants, insert the stoppers, rotate each tube for about 15 minutes, 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 283 nm, with a suitable spectrophotometer zeroed with 0.1 N hydrochloric acid, using the prepared reagent blank. Calculate the quantity, in mg, of C
20H
22N
2·2C
4H
4O
4 in the portion of Tablets taken by the formula:
25C(AU / AS),
in which
C is the concentration, in mg per mL, of
USP Azatadine Maleate RS in the
Standard preparation; and
AU and
AS are the absorbances of the solutions from the
Assay preparation and the
Standard preparation, respectively.
621
) coated with a 0.25-mm layer of chromatographic silica gel mixture. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of toluene, isopropyl alcohol, and diethylamine (10:10:1) 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 plate to air-dry. Examine the plate under short-wavelength UV light: the RF value and intensity of the principal spot in the chromatogram of the test solution correspond to those obtained from the chromatogram of the Standard solution.