A: Adilution of the Injection in methanol containing 1mg of diazoxide per mLresponds to the Thin-layer Chromatographic Identification Test á201ñ,a solution of USP Diazoxide RSin methanol containing 1mg per mLbeing used as the Standard solution.Develop the chromatogram with a solvent system consisting of a mixture of ethyl acetate,methanol,and ammonium hydroxide (17:4:3).

B: The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that of the Standard preparation,both relative to the internal standard,as obtained in the Assay.

Mobile phase,Internal standard solution,Standard preparation,andChromatographic system— Prepare as directed in the Assayunder Diazoxide.

Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 45mg of diazoxide,to a 50-mLvolumetric flask,dilute with methanol to volume,and mix.Transfer 5.0mLof this solution to a 100-mLvolumetric flask,add 2.0mLof Internal standard solution,dilute with a mixture of water and methanol (4:1)to volume,and mix.

Procedure— Proceed as directed for Procedurein the Assayunder Diazoxide.Calculate the quantity,in mg,of C8H7ClN2O2Sin each mLof the Injection taken by the formula: in which Cis the concentration,in µg per mL,of USP Diazoxide RSin the Standard preparation,Vis the volume,in mL,of Injection taken,and RUand RSare the peak response ratios obtained from the Assay preparationand the Standard preparation,respectively.