Montelukast EP Impurity A;Montelukast Sodium (S)-Isomer

Montelukast EP Impurity A;Montelukast Sodium (S)-Isomer

1-[[[(1S)-1-[3-[(1E)-2-(7-Chloro-2-quinolinyl)ethenyl]phenyl]-3-[2-(1-hydroxy-1-methylethyl)phenyl]propyl]thio]methyl]cyclopropaneacetic acid sodium salt

Impurity reference standard used for related substances testing of Montelukast Acid drug substance and drug product per pharmacopoeial limits.