TESTING SPECIFICATION

USP 32

ITEM TESTED

STANDARD

Appearance

White to off-white powder. Freely soluble in dichloromethane

 Identification

Infrared Absorption

The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation , as obtained in the Assay

Specific rotation

Between -28.6° and -35.0°,measured at 20°

Water

Not more than 0.5%

Residue on Ignition

Not more than 0.1%

Heavy metals

Not more than 10ppm

Related compounds by HPLC

(Test 1)

Fructose not more than 0.3%

Compound A not more than 0.3%

Other individual impurity not more than 0.1%

Total impurities not more than 0.5%

Limit of sulfamate and sulfate

Sulfamate ion not more than 0.10%;

Sulfate ion not more than 0.10%.

Assay                                                                

Topiramate contains not less than 98.0% and not more than the equivalent of 102.0% of C12H21NO8S, calculated with reference to the Anhydrous Basis.