Medium: 0.05Mpotassium phosphate buffer,pH7.2,prepared by dissolving 6.8g of monobasic potassium phosphate in 1000mLof water and adjusting with 1Nsodium hydroxide to a pHof 7.2;900mL.

Apparatus 1: 100rpm.

Time: 45minutes.

Procedure— Determine the amount of cefixime (C16H15N5O7S2)dissolved from UVabsorbances at the wavelength of maximum absorbance at about 288nm of filtered portions of the solution under test,suitably diluted with Dissolution Mediumif necessary,in comparison with a Standard solution having a known concentration of USP Cefixime RSin the same medium.[NOTE—An amount of methanol not to exceed 0.1%of the total volume of the Standard solution may be used to bring the Reference Standard into solution prior to dilution with Dissolution Medium,and the solution may be sonicated to assure complete dissolution of the Reference Standard.]

Tolerances— Not less than 75%(Q)of the labeled amount of cefixime (C16H15N5O7S2)is dissolved in 45minutes.

Tetrabutylammonium hydroxide solution,Mobile phase,pH7.0Phosphate buffer,Resolution solution,Standard preparation,and Chromatographic system— Proceed as directed in the Assayunder Cefixime.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 400mg of cefixime,to a 100-mLvolumetric flask,add 75mLof pH7.0Phosphate buffer,and sonicate.Dilute with pH7.0Phosphate bufferto volume,mix,and centrifuge.Transfer 5.0mLof the clear supernatant to a second 100-mLvolumetric flask,dilute with pH7.0Phosphate bufferto volume,and mix.

Procedure— Proceed as directed in the Assayunder Cefixime.Calculate the quantity,in mg,of cefixime (C16H15N5O7S2)in the portion of Tablets taken by the formula: in which the terms are as defined therein.