A:Infrared Absorption á197Fñ.

B:Ultraviolet Absorption á197Uñ—

Test solution: 10mg per mL,in alcohol.

Test solution— Use the Assay preparation.

Chromatographic system— Proceed as directed in the Assay.To evaluate the system suitability requirements,use the Standard preparationprepared as directed in the Assay.

Procedure— Inject a volume (about 1µL)of the Test solutioninto the chromatograph,record the chromatogram,and measure all of the peak responses.Calculate the percentage of each impurity in the portion of Meradimate taken by the formula: in which riis the peak response for each impurity;and rsis the sum of the responses of all the peaks:not more than 0.1%of any individual impurity is found;and not more than 2.0%of total impurities is found.

Standard preparation— Dissolve an accurately weighed quantity of USP Meradimate RSin tert-butyl methyl ether,and dilute quantitatively,and stepwise if necessary,with tert-butyl methyl ether to obtain a solution having a known concentration of about 20.0mg per mL.

Assay preparation— Transfer about 2g of Meradimate,accurately weighed,to a 100-mLvolumetric flask,dilute with tert-butyl methyl ether to volume,and mix.

Chromatographic system (see Chromatography á621ñ)— The gas chromatograph is equipped with a flame-ionization detector and a 0.32-mm ×25-m column coated with a 0.1-µm film of G1.The carrier gas is helium,flowing at a rate of about 6mLper minute.The chromatograph is programmed as follows.Initially the temperature of the column is equilibrated at 60,then the temperature is increased at a rate of 8per minute to 240,and is maintained at 240for 10minutes.The injection port temperature is maintained at 240,and the detector temperature is maintained at 260.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the resolution,R,between meradimate and any other peak is not less than 1.0;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 1µL)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 C17H25NO2in the portion of Meradimate taken by the formula: in which Cis the concentration,in mg per mL,of USP Meradimate RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.