Chromatographic purity—
TEST 1—
Sodium 1-heptanesulfonate solution, System suitability solution, and Chromatographic system—
Proceed as directed in the Assay.
Mobile phase—
Transfer 20.0 mL of
Sodium 1-heptanesulfonate solution, 2.0 mL of triethylamine, and 500 mL of water to a suitable container, mix, adjust with phosphoric acid to a pH of 3.2 ± 0.1, and dilute with water to 625 mL. Transfer to a 1-liter volumetric flask, dilute with acetonitrile to volume, mix, filter, and degas. Make adjustments if necessary (see
System Suitability under
Chromatography 
621
).
Test solution—
Transfer about 100 mg of Clomipramine Hydrochloride, accurately weighed, to a 50-mL volumetric flask, dissolve in and dilute with methanol to volume, and mix.
Procedure—
Inject a volume (about 5 µL) of the
Test solution into the chromatograph, record the chromatogram, and measure all of the peak responses. Calculate the percentage of each impurity in the portion of Clomipramine Hydrochloride taken by the formula:
100(ri / rs),
in which
ri is the peak response for each impurity; and
rs is the sum of the responses of all the peaks.
TEST 2—
Sodium 1-heptanesulfonate solution, Mobile phase, System suitability solution, and Chromatographic system—
Proceed as directed in the Assay.
Test solution—
Prepare as directed for Test 1.
Procedure—
Inject a volume (about 10 µL) of the
Test solution into the chromatograph, record the chromatogram, and measure all of the peak responses. Calculate the percentage of each impurity in the portion of Clomipramine Hydrochloride taken by the formula:
100(ri / rs),
in which
ri is the peak response for each impurity; and
rs is the sum of the responses of all the peaks. Not more than 0.5% of any individual impurity is found; and not more than 2.0% of total impurities is found, the results for
Test 1 and
Test 2 being considered.
Assay—
Sodium 1-heptanesulfonate solution—
Transfer about 5.5 g of sodium 1-heptanesulfonate, accurately weighed, to a 100-mL volumetric flask, dissolve in 50.0 mL of water, and dilute with glacial acetic acid to volume.
Mobile phase—
Transfer 20.0 mL of
Sodium 1-heptanesulfonate solution and 2.0 mL of triethylamine to a 500-mL volumetric flask, and dilute with water to volume. Transfer this solution to a 1-L volumetric flask, adjust with phosphoric acid to a pH of 3.2 ± 0.1, dilute with acetonitrile to volume, mix, filter, and degas. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation—
Dissolve an accurately weighed quantity of
USP Clomipramine Hydrochloride RS in methanol, and dilute quantitatively, and stepwise if necessary, with methanol to obtain a solution having a known concentration of about 0.8 mg per mL. Transfer 10.0 mL of this solution to a 25-mL volumetric flask, dilute with methanol to volume, and mix.
Assay preparation—
Transfer about 80 mg of Clomipramine Hydrochloride, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with methanol to volume, and mix. Transfer 10.0 mL of this solution to a 25-mL volumetric flask, dilute with methanol to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm × 30-cm column that contains packing L1. The flow rate is about 1.0 mL per minute. Chromatograph the
System suitability solution, and record the peak responses as directed for
Procedure: the relative retention times are about 0.85 for desipramine and 1.0 for imipramine; the resolution,
R, between desipramine and imipramine is not less than 0.5; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 10 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of C
19H
23ClN
2·HCl in the portion of Clomipramine Hydrochloride taken by the formula:
250C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Clomipramine Hydrochloride RS in the
Standard preparation; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
;)
100 µg per mL.
for 2 hours: it loses not more than 1.0% of its weight.