» Carisoprodol Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C12H24N2O4.
Packaging and storage Preserve in well-closed containers.
USP Reference standards 11
Identification The retention time of the carisoprodol peak in the chromatogram of the Assay preparation corresponds to that of the carisoprodol peak in the chromatogram of the Standard preparation, obtained as directed in the Assay.
Medium: 0.05 M, pH 6.9 phosphate buffer (see Buffer Solutions in the section Reagents, Indicators, and Solutions) containing 5 units of -amylase per mL; 900 mL. [noteUse only freshly prepared solutions containing -amylase; and equilibrate the Dissolution Medium at 37 for not more than one hour before beginning the Dissolution test. ]
Apparatus 2: 75 rpm.
Time: 60 minutes.
Determine the amount of C12H24N2O4 dissolved employing the following method.
Mobile phase, Resolution solution, and Chromatographic system Prepare as directed in the Assay.
Standard solution [noteA volume of acetonitrile not exceeding 2% of the final total volume of solution may be used to aid in dissolving the carisoprodol. ] Prepare a solution of USP Carisoprodol RS in 0.05 M, pH 6.9 phosphate buffer having an accurately known concentration of about 0.4 mg per mL.
Procedure Separately inject equal volumes (about 150 µL) of the Standard solution and a filtered portion of the solution under test into the chromatograph, record the peak responses, and measure the responses for the major peaks. Calculate the amount of C12H24N2O4 dissolved.
Tolerances Not less than 80% (Q) of the labeled amount of C12H24N2O4 is dissolved in 60 minutes.
Uniformity of dosage units 905: meet the requirements.
Mobile phase Prepare a filtered and degassed mixture of water and acetonitrile (60:40). Make adjustments if necessary (see System Suitability under Chromatography 621).
Diluent Prepare a mixture of methanol and 0.01 N sulfuric acid (60:40).
Standard preparation Dissolve an accurately weighed quantity of USP Carisoprodol RS in Diluent, using sonication, if necessary, to obtain a solution having a known concentration of about 3.5 mg per mL.
Resolution solution Prepare a solution in Mobile phase containing about 2.4 mg of 2-methyl-2-propyl-1,3-propanediol and 3.4 mg of carisoprodol per mL.
Assay preparation Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 350 mg of carisoprodol, to a 100-mL volumetric flask. Add about 50 mL of Diluent, place in an ultrasonic bath for 30 minutes, and shake by mechanical means for 60 minutes. Dilute with Diluent to volume, and mix. Pass a portion of this solution through a membrane filter of 0.5 µm or finer porosity, and use the filtrate as the Assay preparation.
Chromatographic system (see Chromatography 621)The liquid chromatograph is equipped with a refractive index detector and a 3.9-mm × 30-cm column that contains packing L1. Maintain the detector and the column at 30 ± 1. The flow rate is about 2 mL per minute. Chromatograph the Resolution solution and the Standard preparation, and record the peak responses as directed for Procedure: the resolution, R, between the 2-methyl-2-propyl-1,3-propanediol and carisoprodol peaks is not less than 2.0, and the relative standard deviation for three replicate injections of the Standard preparation is not more than 2.0%. The relative retention times are about 0.5 for 2-methyl-2-propyl-1,3-propanediol and 1.0 for carisoprodol.
Procedure [noteUse peak heights where peak responses are indicated. ] Separately inject equal volumes (about 35 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 C12H24N2O4 in the portion of Tablets taken by the formula:
100C(rU / rS)in which C is the concentration, in mg per mL, of USP Carisoprodol RS in the Standard preparation, and rU and rS are the peak responses obtained for carisoprodol from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 2501Pharmacopeial Forum: Volume No. 37(3)