Isoxsuprine Hydrochloride Tablets
» Isoxsuprine Hydrochloride Tablets contain not less than 93.0 percent and not more than 107.0 percent of the labeled amount of C18H23NO3·HCl.
Packaging and storage Preserve in tight containers.
USP Reference standards 11
Identification Transfer a portion of finely powdered Tablets, equivalent to about 10 mg of isoxsuprine hydrochloride, to a 60-mL beaker, add about 20 mL of water, mix, and filter. Transfer the clear filtrate to a 60-mL separator, add 10 mL of pH 9.0 alkaline borate buffer (see Buffer Solutions in the section Reagents, Indicators, and Solutions), and shake vigorously to mix. Extract with 2 mL of chloroform, filter the extract through a pledget of cotton, and mix the filtrate with 500 mg of potassium bromide. Evaporate the chloroform, carefully removing the last trace of solvent in a small vacuum flask: the IR absorption spectrum of a potassium bromide dispersion of the isoxsuprine so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Isoxsuprine Hydrochloride RS that has been treated in the same manner.
Medium: water; 900 mL.
Apparatus 1: 100 rpm.
Time: 45 minutes.
Procedure Determine the amount of C18H23NO3·HCl dissolved from UV absorbances at the wavelength of maximum absorbance at about 269 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 Isoxsuprine Hydrochloride RS in the same medium.
Tolerances Not less than 75% (Q) of the labeled amount of C18H23NO3·HCl is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements.
Buffer solution Transfer about 1.32 g of anhydrous dibasic ammonium phosphate to a 1-liter volumetric flask, add about 950 mL of water, and mix. Adjust with phosphoric acid to a pH of 7.5, dilute with water to volume, and mix.
Mobile phase Prepare a filtered and degassed mixture of methanol and Buffer solution (2:1). Make adjustments if necessary (see System Suitability under Chromatography 621).
Standard preparation Dissolve an accurately weighed quantity of USP Isoxsuprine Hydrochloride RS in Mobile phase, and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 0.4 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 20 mg of isoxsuprine hydrochloride, to a 50-mL volumetric flask, and add about 25 mL of Mobile phase. Shake by mechanical means for 30 minutes, sonicate for ten minutes to dissolve, dilute with Mobile phase to volume, mix, and filter.
Chromatographic system (see Chromatography 621)The liquid chromatograph is equipped with a 274-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 column efficiency is not less than 1800 theoretical plates, and the relative standard deviation for replicate injections is not more than 2.0%.
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 responses for the major peaks. Calculate the quantity, in mg, of C18H23NO3·HCl in the portion of Tablets taken by the formula:
50C(rU / rS)in which C is the concentration, in mg per mL, of USP Isoxsuprine Hydrochloride RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 3602