Identification
Dissolve about 1g of the Capsule contents in 25mLof water,add 5mLof 3Nhydrochloric acid,and wash the precipitate with two 5-mLportions of cold water.Recrystallize from alcohol the precipitate so obtained,and dry at 110

for 1hour:the
p-aminobenzoic acid so obtained melts between 186

and 189

.
Dissolution á711ñ
Medium:
water;900mL.
Apparatus 1:
100rpm.
Time:
45minutes.
Procedure
Determine the amount of C
7H
6KNO
2dissolved by employing UVabsorption at the wavelength of maximum absorbance at about 270nm on filtered portions of the solution under test,suitably diluted with
Medium,in comparison with a Standard solution having a known concentration of
USP Aminobenzoate Potassium RSin the same
Medium.
Tolerances
Not less than 75%(Q)of the labeled amount of C7H6KNO2is dissolved in 45minutes.
Assay
Assay preparation
Remove as completely as possible,and combine,the contents of not fewer than 20Capsules.Transfer an accurately weighed portion of the combined contents,equivalent to about 100mg of aminobenzoate potassium,to a 200-mLvolumetric flask,add 150mLof water,shake by mechanical means for 30minutes,dilute with water to volume,mix,and filter.Pipet 2mLof the filtrate into a 200-mLvolumetric flask,dilute with water to volume,and mix.
Procedure
Concomitantly determine the absorbances of the
Standard preparationand the
Assay preparationat the wavelength of maximum absorbance at about 270nm,with a suitable spectrophotometer,using water as the blank.Calculate the quantity,in mg,of aminobenzoate potassium (C
7H
6KNO
2)in the portion of Capsule contents taken by the formula:
20C(AU/AS),
in which
Cis the concentration,in µg per mL,of
USP Aminobenzoate Potassium RSin the
Standard preparation;and
AUand
ASare the absorbances of the
Assay preparationand the
Standard preparation,respectively.