A: Transfer a portion of Capsule contents,equivalent to about 85mg of fenoprofen,to a 125-mLseparator containing 5mLof acetone and 2mLof 6Nhydrochloric acid.Swirl to dissolve,add 15mLof water,and extract with three 15-mLportions of chloroform,draining each chloroform extract through a layer of about 2g of anhydrous sodium sulfate,supported on glass wool and previously washed with chloroform,into a 50-mLvolumetric flask.Rinse the sodium sulfate filter with about 2mLof chloroform,collect the rinsing with the combined chloroform extracts,dilute with chloroform to volume,and mix.Transfer this solution to a suitable flask,and evaporate on a water bath with the aid of a current of air to dryness:the IRabsorption spectrum of a film of the liquid residue thus obtained between sodium chloride plates exhibits maxima only at the same wavelengths as that of a similar preparation of USP Fenoprofen Calcium RS.

B: Place an amount of Capsule contents,equivalent to about 300mg of fenoprofen,in a suitable container,and dissolve in 10mLof acetone.Filter the solution through paper,and collect the filtrate in a crucible.Carefully evaporate to dryness,and ignite the crucible and its contents.Dissolve the residue in 10mLof 1Nhydrochloric acid,transfer the solution to a beaker,add 2drops of methyl red TS,neutralize with 6Nammonium hydroxide,and add 3Nhydrochloric acid dropwise until the solution is acid to the indicator.Upon the addition of ammonium oxalate TS,a white precipitate is formed.The residue so obtained is insoluble in acetic acid but dissolves in hydrochloric acid.

Medium: pH7.0phosphate buffer (see Buffer Solutionsin the section Reagents,Indicators,and Solutions);1000mL.

Apparatus 1: 10-mesh basket;100rpm.

Time: 60minutes.

Procedure— Filter 20mLof the solution under test,and transfer 5.0mLof the filtrate to a 25-mLvolumetric flask.Dilute with Dissolution Mediumto volume,and mix.Determine the absorbances of this solution and a Standard solution prepared from USP Fenoprofen Sodium RS,in the same medium having a known concentration of about 60µg per mL,at the wavelength of maximum absorbance at about 270nm,using Dissolution Mediumas the blank.Calculate the amount of C15H14O3dissolved,in mg,by the formula: in which 242.28is the molecular weight of fenoprofen;264.26is the molecular weight of anhydrous fenoprofen sodium;Cis the concentration of anhydrous fenoprofen sodium in the Standard solution,as determined from the concentration of USP Fenoprofen Sodium RScorrected for moisture content by a titrimetric water determination;and AUand ASare the absorbances of the solutions obtained from the substance under test and the USP Reference Standard,respectively.

Tolerances— Not less than 75%(Q)of the labeled amount of C15H14O3is dissolved in 60minutes.

Mobile phase,Diluting solution,Resolution solution,Standard preparation,and Chromatographic system— Proceed as directed in the Assayunder Fenoprofen Calcium.

Assay preparation— Weigh the contents of not fewer than 20Capsules,and calculate the average weight per Capsule.Mix the combined contents of the Capsules,and transfer an accurately weighed portion,equivalent to about 150mg of fenoprofen,to a 250-mLvolumetric flask.Add about 200mLof Diluting solution,and sonicate for about 15minutes.Allow to cool,dilute with Diluting solutionto volume,mix,and pass through a suitable filter,discarding the first 10mLof the filtrate.Use the clear filtrate as the Assay preparation.

Procedure— Proceed as directed in the Assayunder Fenoprofen Calcium.Calculate the quantity,in mg,of fenoprofen (C15H14O3)in the portion of Capsules taken by the formula: in which 484.55is two times the molecular weight of fenoprofen;522.61is the molecular weight of fenoprofen calcium;and the other terms are as defined therein.