C7H5KO2 160.21

Benzoic acid,potassium salt.
Potassium benzoate [582-25-2].

Packaging and storage— Preserve in well-closed containers.

Identification— It responds to the flame test for Potassium á191ñand to the tests for Benzoate á191ñ.

Alkalinity— Dissolve 2g in 20mLof hot water,and add 2drops of phenolphthalein TS:the pink color produced,if any,is discharged by the addition of 0.20mLof 0.10Nsulfuric acid.

Water,Method Iá921ñ: not more than 1.5%.

Heavy metals á231ñ— Dissolve 4.0g in 40mLof water,add,dropwise,with vigorous stirring,10mLof 3Nhydrochloric acid,and filter.Use 25mLof the filtrate:the limit is 0.001%.

Organic volatile impurities,Method Iá467ñ: meets the requirements.

Assay— Transfer about 600mg of Potassium Benzoate,accurately weighed,to a 250-mLbeaker.Add 100mLof glacial acetic acid,stir until the assay specimen is completely dissolved,add 2drops of crystal violet TS,and titrate with 0.1Nperchloric acid VS.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 16.02mg of C7H5KO2.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 3065

Phone Number:1-301-816-8262