Procedure for content uniformity—
Transfer 1 finely powdered Tablet to a 100-mL volumetric flask with the aid of 70 mL of dilute hydrochloric acid (1 in 100), and shake by mechanical means for 30 minutes. Add dilute hydrochloric acid (1 in 100) to volume, mix, and filter, if necessary, discarding the first 20 mL of the filtrate. Transfer an aliquot of the filtrate, equivalent to about 2.5 mg of imipramine hydrochloride, to a 100-mL volumetric flask, add dilute hydrochloric acid (1 in 100) to volume, and mix. Dissolve an accurately weighed quantity of
USP Imipramine Hydrochloride RS in dilute hydrochloric acid (1 in 100), and dilute quantitatively and stepwise with the same solvent to obtain a Standard solution having a known concentration of about 25 µg per mL. Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 250 nm, with a suitable spectrophotometer, using dilute hydrochloric acid (1 in 100) as the blank. Calculate the quantity, in mg, of C
19H
24N
2·HCl in the Tablet by the formula:
10(C / V)(AU / AS),
in which
C is the concentration, in µg per mL, of
USP Imipramine Hydrochloride RS in the Standard solution;
V is the volume, in mL, of the aliquot taken of the solution from the Tablet; and
AU and
AS are the absorbances of the solution from the Tablet and the Standard solution, respectively.
for 30 minutes: the precipitate so obtained meets the requirements for Identification test A under Imipramine Hydrochloride.
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