Medium: simulated gastric fluid TS,prepared without pepsin;900mL.

Apparatus 1: 50rpm.

Time: 45minutes.

Procedure— Determine the amount of C15H13N3O4Sdissolved from UVabsorbances at the wavelength of maximum absorbance at about 333nm of suitably 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 Piroxicam RSin the same medium.[NOTE—Use a suitable filter that does not adsorb piroxicam.To prepare the Standard solution,dissolve a suitable,accurately weighed quantity of USP Piroxicam RSin methanol to obtain a stock solution having a known concentration of about 0.5mg per mLprior to dilution with Dissolution Medium.]

Tolerances— Not less than 75%(Q)of the labeled amount of C15H13N3O4Sis dissolved in 45minutes.

Buffer,Mobile phase,Standard preparation,and Chromatographic system— Prepare as directed in the Assayunder Piroxicam.

Assay preparation— Transfer,as completely as possible,the contents of not less than 20Capsules to a suitable tared container,and determine the average weight per capsule.Mix the combined contents,and transfer an accurately weighed portion,equivalent to about 50mg of piroxicam,to a 100-mLvolumetric flask.Add about 70mLof 0.01Nmethanolic hydrochloric acid,and shake by mechanical means for 30minutes.Dilute with 0.01Nmethanolic hydrochloric acid to volume,and mix.Centrifuge a portion of this mixture to obtain a clear solution.Transfer 10.0mLof the solution so obtained to a 100-mLvolumetric flask,add about 50mLof 0.01Nmethanolic hydrochloric acid and 20.0mLof water,dilute with 0.01Nmethanolic hydrochloric acid to volume,and mix.

Procedure— Proceed as directed for Procedurein the Assayunder Piroxicam.Calculate the quantity,in mg,of C15H13N3O4Sin the portion of the contents of Capsules taken by the formula: in which Cis the concentration,in mg per mL,of USP Piroxicam RSin the Standard preparation,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.