Reference Standard
| CAS Number | Not assigned |
| Formula | Structurally related to zafirlukast |
| Molecular Weight | ~550–590 g/mol (approximate) |
| Purity | ≥95% |
| Storage | Store at 2–8 °C; protect from light |
A process- or degradation-related impurity of zafirlukast observed during synthesis or stability testing.
Used for impurity identification, quantification, and analytical method validation.
HPLC impurity profiling, LC-MS, NMR where applicable.
