ITEM

STANDARD

RESULTS

Appearance

White or off-white crystalline powder

White or off-white Crystalline  powder

Identification

UV：similar to reference

 standard(258+/-2nm)

IR: similar to the reference standard

Conforms

Reside on ignition

≤0.1%

0.05%

Heavy metals

≤20ppm

Conforms

Loss on drying

≤0.3%

0.14%

Melting point

164-168℃

166-167℃

5-Methylisoxazole-carboxylic acid

Leflunomide related compound A

Leflunomide related compound B

N-(2’-Trifluoromethylphenyl)-5-

methylisoxzole-4-carboxomide

2-Cyano-acetic acid-(4’-

trifluoromethyl)-anilide

Leflunomide related compound C

Total impuritie（excluding

leflunomide related compound B and leflunomide related compound C）

Any other individual impurity

Total impurities

≤0.1%

≤0.01%

≤0.3%

≤0.1%

≤0.1%

≤0.1%

≤0.2%

≤0.1%

≤0.4%

Conforms

ASSAY

98.0-102.0%

99.80%

Conclusion: Conforms to the USP32 standard