Item

Standard

Appearance

White to off-white powder,freely soluble in dichloromethane

indentification

Infrared absorption

The retention time of the major peak of the sample solution corresponds to that of the standard solution,as obtained in the Assay

Residue on ignition

Not more than 0.2%

Heavy metals

Not more than 10ppm

Related compounds by HPLC(procedure 2)

Fructose not more than 0.3%

Compound A not more than 0.3%

Individual unknown not more than 0.1%

Total impurities not more than 0.5%

Specific rotation

Between -26° and -35°,measured at 20°

Water

            Not more than 0.5%

Limit of sulfamate and sulfate

Sulfamate 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