Montelukast is used for a number of conditions including asthma, exercise induced bronchospasm, allergic rhinitis, primary dysmenorrhoea (i.e. dysmenorrhoea not associated with known causes; see dysmenorrhea causes), and urticaria.It is mainly used as a complementary therapy in adults in addition to inhaled corticosteroids, if they alone do not bring the desired effect. It is also used to prevent allergic reactions and asthma flare-ups during the administration of intravenous immunoglobulin.

• Description : White or off-white powder
• Assay: ≥99.0%
• Identification:
• Chemistry: Must conforms to standard
• Identification (HPLC): The retention time of test sample major peak complies to reference standard
• Infrared absorption : Must complies to reference standard
• Sodium identification: The solution so obtained responds to the tests for sodium
• pH : 9.0~10.5
• Impurity : Not more than 0.5% of any individual impurity is found,
  the sum of all impurities found is not more than 1.0%
• S-isomer : NMT 1.0%
• Heavy metals : NMT 20ppm
• Loss on drying : NMT 1.0%
• microbe :
• Bacterium : NMT 1000 cfu/g
• Mildew : NMT 100 cfu/g
• Coliform :NMT 0 cfu/g