Carbinoxamine Maleate Tablets
» Carbinoxamine Maleate Tablets contain not less than 93.0 percent and not more than 107.0 percent of the labeled amount of C16H19ClN2O·C4H4O4.
Packaging and storage Preserve in tight, light-resistant containers.
Identification A solution of carbinoxamine maleate (1 in 50,000) in dilute sulfuric acid (1 in 70) prepared from the Tablets as directed under Salts of Organic Nitrogenous Bases 501 exhibits an absorbance maximum at 263 ± 2 nm. The absorptivity at 263 nm is within 7.0% of that of a 1 in 50,000 solution of USP Carbinoxamine Maleate RS in dilute sulfuric acid (1 in 70), similarly measured.
Medium: water; 900 mL.
Apparatus 2: 50 rpm.
Time: 45 minutes.
Procedure Determine the amount of C16H19ClN2O·C4H4O4 dissolved from UV absorbances at the wavelength of maximum absorbance at about 260 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 Carbinoxamine Maleate RS in the same medium.
Tolerances Not less than 75% (Q) of the labeled amount of C16H19ClN2O·C4H4O4 is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements.
Procedure for content uniformity Place 1 Tablet in a 100-mL volumetric flask, add 10.0 mL of water, and shake by mechanical means for 15 minutes. Dilute with methanol to volume, and filter, discarding the first 20 mL of the filtrate. Dilute a portion of the subsequent filtrate quantitatively and stepwise, if necessary, with a mixture of methanol and water (9:1) to obtain a solution containing about 40 µg of carbinoxamine maleate per mL. Concomitantly determine the absorbances of this solution and of a Standard solution of USP Carbinoxamine Maleate RS, in the same medium having a known concentration of about 40 µg per mL, in 1-cm cells, at the wavelength of maximum absorbance at about 260 nm, with a suitable spectrophotometer, using a mixture of methanol and water (9:1) as the blank. Calculate the quantity, in mg, of C16H19ClN2O·C4H4O4 in the Tablet taken by the formula:
(TC / D)(AU / AS)in which T is the labeled quantity, in mg, of carbinoxamine maleate in the Tablet; C is the concentration, in µg per mL, of USP Carbinoxamine Maleate RS in the Standard solution; D is the concentration, in µg per mL, of carbinoxamine maleate in the solution from the Tablet, based upon the labeled quantity per Tablet and the extent of dilution; and AU and AS are the absorbances of the solution from the Tablet and the Standard solution, respectively.
Assay Weigh and finely powder not less than 30 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 100 mg of carbinoxamine maleate, to a separator, add 35 mL of water and 3 g of sodium bicarbonate, and mix. Extract with five 20-mL portions of chloroform, filtering the extracts through a pledget of cotton. Evaporate the combined chloroform extracts on a steam bath just to dryness, dissolve the residue in 50 mL of glacial acetic acid, add 1 drop of crystal violet TS, and titrate with 0.05 N perchloric acid VS to a blue-green endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.05 N perchloric acid is equivalent to 10.17 mg of C16H19ClN2O·C4H4O4.
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USP32NF27 Page 1792