Imipramine Hydrochloride Injection
» Imipramine Hydrochloride Injection is a sterile solution of Imipramine Hydrochloride in Water for Injection. It contains, in each mL, not less than 11.5 mg and not more than 13.5 mg of C19H24N2·HCl.
Packaging and storage— Preserve in single-dose containers, preferably of Type I glass.
Identification— Transfer 10 mL of Injection to a separator, add 2 mL of 2 N hydrochloric acid, extract with 10 mL of chloroform, filter, and evaporate the chloroform solution to about 2 mL. Carefully add ether until the liquid becomes turbid, heat on a steam bath to produce a clear solution, then cool, and allow to stand. Filter the crystalline precipitate, wash with ether, and dry in vacuum at 105 for 30 minutes: the precipitate so obtained responds to Identification test A under Imipramine Hydrochloride.
Bacterial endotoxins 85 It contains not more than 5.0 USP Endotoxin Units per mg of imipramine hydrochloride.
pH 791: between 4.0 and 5.0.
Other requirements— It meets the requirements under Injections 1.
Assay— Transfer an accurately measured volume of Injection, equivalent to about 25 mg of imipramine hydrochloride, to a 100-mL volumetric flask, add 0.5 N hydrochloric acid to volume, and mix. Pipet 10 mL of this solution into a separator, add 10 mL of 1 N sodium hydroxide, and extract with four 20-mL portions of ether, shaking each portion for 2 minutes and collecting the extracts in a second separator. Extract the combined ether extracts with four 20-mL portions of 0.5 N hydrochloric acid, and combine the extracts in a 250-mL beaker. Aerate this solution with nitrogen to remove residual ether, then transfer to a 100-mL volumetric flask, and rinse the beaker with 0.5 N hydrochloric acid, collecting the rinsings in the flask. Add the 0.5 N acid to volume, and mix. Dissolve an accurately weighed quantity of USP Imipramine Hydrochloride RS in 0.5 N hydrochloric acid, 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 0.5 N hydrochloric acid as the blank. Calculate the quantity, in mg, of C19H24N2·HCl in each mL of the Injection taken by the formula:
(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 Injection taken; and AU and AS are the absorbances of the solution from the Injection and the Standard solution, respectively.
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