Identification—
A:
The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
B:
A filtered solution of finely powdered Tablets, equivalent to protriptyline hydrochloride solution (1 in 20), meets the requirements of the tests for
Chloride 
191
, when tested as specified for alkaloidal hydrochlorides.
Dissolution 711—
Medium:
water; 900 mL.
Apparatus 1:
100 rpm.
Time:
45 minutes.
Procedure—
Determine the amount of C
19H
21N·HCl dissolved from UV absorbances at the wavelength of maximum absorbance at about 290 nm of filtered portions of the solution under test, suitably diluted with
Dissolution Medium, if necessary, in comparison with a Standard solution having a known concentration of
USP Protriptyline Hydrochloride RS in the same medium.
Tolerances—
Not less than 75% (Q) of the labeled amount of C19H21N·HCl is dissolved in 45 minutes.
Uniformity of dosage units 905:
meet the requirements.
PROCEDURE FOR CONTENT UNIFORMITY—
Solution A
, Solution B, Mobile phase, Diluent, Standard preparation, and Chromatographic system—Proceed as directed in the Assay.
Test preparation—
Transfer 1 finely powdered Tablet to a 50-mL volumetric flask, add about 1 mL of 2.5 N hydrochloric acid and 5 mL of water for each 5 mg of protriptyline hydrochloride, and shake by mechanical means for 20 minutes or until the Tablet is fully disintegrated. Add 5 mL of alcohol for each 5 mg of protriptyline hydrochloride, and shake for an additional 10 minutes. Dilute with water to volume, mix, and pass through a 0.45-µm membrane filter, discarding the first 1.5 mL of the filtrate. Use the subsequent filtrate as the Test preparation.
Procedure—
Proceed as directed in the
Assay. Calculate the quantity, in mg, of protriptyline hydrochloride (C
19H
21N·HCl) in the Tablet taken by the formula:
(TC / D)(rU / rS),
in which
T is the labeled quantity, in mg, of protriptyline hydrochloride in the Tablet;
C is the concentration, in µg per mL, of
USP Protriptyline Hydrochloride RS in the
Standard preparation; D is the concentration, in µg per mL, of protriptyline hydrochloride in the
Test preparation, based on the labeled quantity per Tablet and the extent of dilution; and
rU and
rS are the peak responses obtained from the
Test preparation and the
Standard preparation, respectively.
Assay—
Solution A—
Prepare a filtered and degassed solution of 22.0 g of monobasic sodium phosphate and 3.78 g of sodium 1-hexanesulfonate in 1900 mL of water. Adjust with phosphoric acid to a pH of 2.90, and dilute with water to volume in a 2000-mL volumetric flask. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Solution B—
Use filtered and degassed acetonitrile. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Mobile phase—
Use variable mixtures of
Solution A and
Solution B as directed for
Chromatographic system.
Diluent—
Add 200 mL of alcohol to a 1000-mL volumetric flask. Add 40 mL of 2.5 N hydrochloric acid, dilute with water to volume, and mix.
Standard preparation—
Dissolve an accurately weighed quantity of
USP Protriptyline Hydrochloride RS in
Diluent, and dilute quantitatively, and stepwise if necessary, with
Diluent to obtain a solution having a known concentration of about 0.20 mg per mL.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 40 mg of protriptyline hydrochloride, to a 200-mL volumetric flask, add 40 mL of alcohol, and shake by mechanical means for 5 minutes. Add 40 mL of water and 8 mL of 2.5 N hydrochloric acid, and shake for an additional 10 minutes. Dilute with water to volume, and mix. Pass through a 0.45-µm membrane filter, discarding the first 5 mL of the filtrate. Use the subsequent filtrate as the Assay preparation.
Chromatographic system
(see
Chromatography 621)—The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm × 15-cm column containing 5-µm base-deactivated packing L7. The flow rate is about 1.5 mL per minute. The chromatograph is programmed as follows.
Time
(minutes) |
Solution A
(%) |
Solution B
(%) |
Elution |
| 0 |
83 |
17 |
equilibration |
| 0-15 |
83®50 |
17®50 |
linear gradient |
| 15-20 |
50 |
50 |
isocratic |
| 20-25 |
50®83 |
50®17 |
linear gradient |
| 25-30 |
83 |
17 |
re-equilibration |
Chromatograph the
Standard preparation and record the peak responses as directed for
Procedure: the column efficiency is not less than 25,000 theoretical plates; the tailing factor is not more than 2.5; and the relative standard deviation is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Assay preparation and the
Standard preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of protriptyline hydrochloride (C
19H
21N·HCl) in the portion of Tablets taken by the formula:
200C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Protriptyline Hydrochloride RS in the
Standard preparation; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
