Medium: water;900mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Procedure— Determine the amount of C16H19ClN2O·C4H4O4dissolved from UVabsorbances at the wavelength of maximum absorbance at about 260nm 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 RSin the same medium.

Tolerances— Not less than 75%(Q)of the labeled amount of C16H19ClN2O·C4H4O4is dissolved in 45minutes.

Procedure for content uniformity— Place 1Tablet in a 100-mLvolumetric flask,add 10.0mLof water,and shake by mechanical means for 15minutes.Dilute with methanol to volume,and filter,discarding the first 20mLof 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 40µg 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 40µg per mL,in 1-cm cells,at the wavelength of maximum absorbance at about 260nm,with a suitable spectrophotometer,using a mixture of methanol and water (9:1)as the blank.Calculate the quantity,in mg,of C16H19ClN2O·C4H4O4in the Tablet taken by the formula: in which Tis the labeled quantity,in mg,of carbinoxamine maleate in the Tablet,Cis the concentration,in µg per mL,of USP Carbinoxamine Maleate RSin the Standard solution,Dis 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 AUand ASare the absorbances of the solution from the Tablet and the Standard solution,respectively.