Medium: pH8.60buffer,prepared by mixing 2.3volumes of 0.2Msodium hydroxide with 2.5volumes of 0.2Mmonobasic potassium phosphate and 2.0volumes of methanol,cooling,mixing with water to obtain 10volumes of solution,and adjusting,if necessary,by the addition of 1Nsodium hydroxide to a pHof 8.60±0.05.The initial volume for the test is 900mL.

Apparatus 2: 60rpm.

Time: 30minutes.

Procedure— Determine the amount of C12H12N2O3dissolved from UVabsorbances at the wavelength of maximum absorbance at about 258nm of filtered portions of the solution under test,suitably diluted with 0.01Nsodium hydroxide,if necessary,in comparison with a Standard solution of known concentration of USP Nalidixic Acid RSin 0.01Nsodium hydroxide,using as the blank a mixture of Dissolution Mediumand 0.01Nsodium hydroxide in the same proportions as present in the test solution.

Tolerances— Not less than 80%(Q)of the labeled amount of C12H12N2O3is dissolved in 30minutes.

Mobile phase ,Internal standard solution,Standard preparation,and Chromatographic system—Proceed as directed in the Assayunder Nalidixic Acid Oral Suspension.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 150mg of nalidixic acid,to a 500-mLvolumetric flask,add about 400mLof methanol,and sonicate for about 30minutes.Shake by mechanical means for about 30minutes,sonicate again for about 30minutes,dilute with methanol to volume,mix,and filter.Transfer 3.0mLof the clear filtrate and 1.0mLof Internal standard solutionto a 25-mLvolumetric flask,dilute with methanol to volume,and mix.

Procedure— Proceed as directed for Procedurein the Assayunder Nalidixic Acid Oral Suspension.Calculate the quantity,in mg,of C12H12N2O3in the portion of Tablets taken by the formula: in which the terms are as defined therein.