A: Aquantity of finely powdered Tablets,equivalent to about 10mg of tolmetin,responds to Identificationtest Aunder Tolmetin Sodium Capsules.

B: The chromatogram of the Assay preparationobtained as directed in the Assayexhibits a major peak for tolmetin,the retention time of which corresponds to that exhibited in the chromatogram of the Standard preparationobtained as directed in the Assay.

Medium ,Apparatus,Time,and Procedure—Proceed as directed in the test for Dissolutionunder Tolmetin Sodium Capsules.

Tolerances— Not less than 75%(Q)of the labeled amount of C15H15NO3is dissolved in 30minutes.

pH2.7buffer solution,Mobile phase,Solvent mixture,Standard preparation,Resolution solution,and Chromatographic system— Prepare as directed in the Assayunder Tolmetin Sodium Capsules.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 60mg of tolmetin,to a 100-mLvolumetric flask.Add about 75mLof Solvent mixture,and shake by mechanical means for 30minutes.Dilute with Solvent mixtureto volume,mix,and filter through a filter having a porosity of 0.45µm or less.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C15H15NO3in the portion of Tablets taken by the formula: in which Cis the concentration,in mg per mL,of USP Tolmetin Sodium RSin the Standard preparation,257.29and 279.27are the molecular weights of tolmetin and anhydrous tolmetin sodium,respectively,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.