Identification—
Transfer a portion of finely powdered Tablets,equivalent to about 100mg of propoxyphene napsylate,to a small flask,and mix with 10mLof chloroform.Add 10mLof
pH12.5borate buffer(prepared as directed in the
Assayunder
Propoxyphene Napsylate),shake for 3minutes,allow to stand until most of the emulsion has broken,and filter the chloroform solution:the chloroform solution is dextrorotatory (see
Optical Rotation á781ñ).
Dissolution á711ñ—
Apparatus 1:
100rpm.
Time:
60minutes.
Determine the amount of C22H29NO2·C10H8O3S·H2Odissolved by employing the following method.
Diethylamine phosphate buffer,Mobile phase,andChromatographic system—
Proceed as directed in the Assay.
Standard solution—
Dissolve an accurately weighed quantity of
USP Propoxyphene Napsylate RSin
Dissolution Mediumto obtain a solution having a known concentration of about 0.1mg per mL.
Test solution—
Quantitatively dilute a filtered portion of the solution under test with Dissolution Mediumto obtain a solution having a concentration of about 0.1mg of propoxyphene napsylate per mL.
Procedure—
Separately inject equal volumes (about 20µL)of the
Standard solutionand the
Test solutioninto the chromatograph,record the chromatograms,and measure the areas for the propoxyphene peaks.Calculate the quantity,in mg,of C
22H
29NO
2·C
10H
8O
3S·H
2Odissolved by the formula:
(565.72/547.72)500CD(rU/rS),
in which 565.72and 547.72are the molecular weights of propoxyphene napsylate and anhydrous propoxyphene napsylate,respectively;
Cis the concentration,in mg per mL,of
USP Propoxyphene Napsylate RSin the
Standard solution;Dis the dilution factor used to prepare the
Test solution;and
rUand
rSare the peak responses obtained from the
Test solutionand the
Standard solution,respectively.
Tolerances—
Not less than 75%(Q)of the labeled amount of C22H29NO2·C10H8O3S·H2Ois dissolved in 60minutes.
Assay—
Diethylamine phosphate buffer—
Mix 5.0mLof diethylamine with 995mLof water,and adjust with phosphoric acid to a pHof 3.2.
Diluent—
Prepare a mixture of Diethylamine phosphate bufferand acetonitrile (4:1).
Mobile phase—
Prepare a mixture of
Diethylamine phosphate bufferand acetonitrile (3:2).Sonicate for 15minutes,and pass through a filter having a 0.5-µm or finer porosity.Make adjustments if necessary (see
System Suitabilityunder
Chromatography á621ñ).
Standard preparation—
Dissolve an accurately weighed quantity of
USP Propoxyphene Napsylate RSin
Diluentto obtain a solution having a known concentration of about 0.1mg per mL.
Assay preparation—
Weigh and finely powder not fewer than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 5Tablets,to a 1000-mLvolumetric flask.Dissolve in and dilute with Diluentto volume,and mix.Further dilute 10.0mLof the resulting solution with Diluent,mix,and filter or centrifuge to obtain a clear solution having a concentration of about 0.1mg per mL.
Chromatographic system(see Chromatography á621ñ)—
The liquid chromatograph is equipped with a 217-nm detector and a 3.9-mm ×30-cm column containing packing L1.The flow rate is about 1mLper minute.Chromatograph the
Standard preparation,and record the responses as directed for
Procedure:the tailing factor is not more than 1.5;and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20µL)of the
Standard preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the areas for the propoxyphene peaks.Calculate the quantity,in mg,of propoxyphene napsylate (C
22H
29NO
2·C
10H
8O
3S·H
2O)in the portion of the Tablets taken by the formula:
(565.72/547.72)1000CD(rU/rS),
in which 565.72and 547.72are the molecular weights of propoxyphene napsylate monohydrate and anhydrous propoxyphene napsylate,respectively;
Cis the concentration,in mg per mL,of
USP Propoxyphene Napsylate RSin the
Standard preparation;Dis the dilution factor used to prepare the
Assay preparation;and
rUand
rSare the responses obtained from the
Assay preparationand the
Standard preparation,respectively.