Procedure for content uniformity
Transfer 1finely powdered Tablet to a 100-mLvolumetric flask with the aid of 70mLof dilute hydrochloric acid (1in 100),and shake by mechanical means for 30minutes.Add dilute hydrochloric acid (1in 100)to volume,mix,and filter,if necessary,discarding the first 20mLof the filtrate.Transfer an aliquot of the filtrate,equivalent to about 2.5mg of imipramine hydrochloride,to a 100-mLvolumetric flask,add dilute hydrochloric acid (1in 100)to volume,and mix.Dissolve an accurately weighed quantity of
USP Imipramine Hydrochloride RSin dilute hydrochloric acid (1in 100),and dilute quantitatively and stepwise with the same solvent to obtain a Standard solution having a known concentration of about 25µg per mL.Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 250nm,with a suitable spectrophotometer,using dilute hydrochloric acid (1in 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
Cis the concentration,in µg per mL,of
USP Imipramine Hydrochloride RSin the Standard solution;
Vis the volume,in mL,of the aliquot taken of the solution from the Tablet;and
AUand
ASare the absorbances of the solution from the Tablet and the Standard solution,respectively.