Propoxyphene Napsylate Oral Suspension
» Propoxyphene Napsylate Oral Suspension contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of propoxyphene napsylate (C22H29NO2·C10H8O3S·H2O).
Packaging and storage— Preserve in tight containers, protected from light. Avoid freezing.
USP Reference standards 11
USP Propoxyphene Napsylate RS Click to View Structure
Identification— Transfer a volume of Oral Suspension, equivalent to about 100 mg of propoxyphene napsylate, to a small flask, mix with 10 mL of chloroform, and filter: the chloroform solution is dextrorotatory (see Optical Rotation 781).
Uniformity of dosage units 905
for oral suspension packaged in single-unit containers: meets the requirements.
Deliverable volume 698
for oral suspension packaged in multiple-unit containers: meets the requirements.
Alcohol content, Method II 611: between 0.5% and 1.5% of C2H5OH.
Diethylamine phosphate buffer, Diluent, Mobile phase, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Propoxyphene Napsylate Tablets.
Assay preparation— Transfer an accurately weighed quantity of the well-mixed Oral Suspension, equivalent to about 50 mg of propoxyphene napsylate monohydrate, to a 100-mL volumetric flask. Dissolve in and dilute with a solution of acetonitrile in water (2 in 5) to volume, and mix. Further dilute 10.0 mL of the resulting solution to 50 mL with the solution of acetonitrile in water (2 in 5).
Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the areas for the propoxyphene peaks. Calculate the quantity, in mg, of propoxyphene napsylate (C22H29NO2·C10H8O3S·H2O) in each mL of the Oral Suspension taken by the formula:
(565.72/547.72)500C(D/WU)(rU / rS)
in which 565.72 and 547.72 are the molecular weights of propoxyphene napsylate and anhydrous propoxyphene napsylate, respectively; C is the concentration, in mg per mL, of anhydrous USP Propoxyphene Napsylate RS in the Standard preparation; D is the density, in g per mL, of the Oral Suspension; WU is the weight, in g, of the Oral Suspension taken; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Clydewyn M. Anthony, Ph.D.
Senior Scientific Liaison
(SM22010) Monographs - Small Molecules 2
Reference Standards RS Technical Services
USP35–NF30 Page 4458
Pharmacopeial Forum: Volume No. 30(1) Page 171