Related compounds
Mobile phase and Chromatographic system
Proceed as directed in the Assay.
Standard stock solution
Accurately weigh about 10 mg each of
USP Propoxyphene Related Compound A RS and USP Propoxyphene Related Compound B RS into a 50-mL volumetric flask, dissolve using 2 mL of methanol, dilute with
Mobile phase to volume, and mix.
Standard solution
Transfer 5.0 mL of the Standard stock solution to a 50-mL volumetric flask, dilute with Mobile phase to volume, and mix.
Test solution
Use the Assay preparation.
Chromatographic system
Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.63 for propoxyphene related compound A, 0.78 for propoxyphene related compound B, and 1.0 for propoxyphene hydrochloride; the resolution, R, between propoxyphene related compound B and propoxyphene related compound A is not less than 2.0; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 50 µL) of the
Test solution and the
Standard solution into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the quantity, in mg, of propoxyphene related compound A in the portion of Propoxyphene Hydrochloride taken by the formula:
50C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Propoxyphene Related Compound A RS in the
Standard solution; and
rU and
rS are the propoxyphene related compound A peak responses obtained from the
Test solution and
Standard solution, respectively. Not more than 0.5% of propoxyphene related compound A is found. Calculate the quantity, in mg, of propoxyphene related compound B as the hydrochloride in the portion of Propoxyphene Hydrochloride taken by the formula:
50C(361.93/325.45)(rU / rS),
in which
C is the concentration, in mg per mL, of USP Propoxyphene Related Compound B RS in the
Standard solution; 361.93 and 325.45 are the molecular weights of propoxyphene related compound B as the hydrochloride and propoxyphene related compound B, respectively; and
rU and
rS are the propoxyphene related compound B peak responses obtained from the
Test solution and the
Standard solution, respectively. Not more than 0.6% of propoxyphene related compound B as the hydrochloride is found.
Assay
0.1 M Monobasic ammonium phosphate buffer, pH 6.3
Dissolve 11.5 g of monobasic ammonium phosphate and 1.0 mL of triethylamine in 1000 mL of water, adjust with 10% sodium hydroxide to a pH of 6.3 ± 0.05, and mix.
Mobile phase
Prepare a filtered and degassed mixture of methanol and
0.1 M Monobasic ammonium phosphate buffer, pH 6.3 (67:33). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation
Dissolve an accurately weighed quantity of
USP Propoxyphene Hydrochloride RS in
Mobile phase to obtain a solution having a known concentration of about 5.0 mg per mL.
Assay preparation
Transfer about 250 mg of Propoxyphene Hydrochloride, accurately weighed, to a 50-mL volumetric flask, dissolve in and dilute with Mobile phase 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 1.5 mL per minute. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the retention time of propoxyphene hydrochloride is about 9 minutes; the tailing factor for the propoxyphene hydrochloride peak is not more than 3.5; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 50 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
22H
29NO
2·HCl in the portion of Propoxyphene Hydrochloride taken by the formula:
50C(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Propoxyphene Hydrochloride RS in the
Standard preparation; and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.