| CAS No. | CATO-C4X-164918 |
| Molecular Formula | C4H7FN2O4 |
| Molecular Weight | 166.11 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Fluorouracil Impurity 18 (C4H7FN2O4) contains a carbohydrate-derived structure, an amide group, fluorine substitution. It is notably hygroscopic, halogen substitution raises its density and boiling point, the carboxyl group imparts weak acidity; these physicochemical properties determine the optimal preparation and storage of its standard solutions. Halogen substitution (F/Cl/Br/I) produces a distinctive isotope pattern in mass spectrometry, a valuable aid for qualitative confirmation.
Fluorouracil Impurity 18 (CAS CATO-C4X-164918) is a certified pharmaceutical impurity reference standard with the molecular formula C4H7FN2O4 and a molecular weight of 166.11 g/mol.
This reference standard supports related-substances testing and method development in line with ICH Q3A/Q3B guidance on impurity control, and is suitable for system suitability testing and forced-degradation studies.
The assigned purity is verified by mass-balance and quantitative NMR (qNMR) approaches, with the expanded uncertainty reported at a 95% confidence level (k=2). Batch homogeneity and stability are independently assessed for every lot.
| Molecular Formula | C4H7FN2O4 |
| Molecular Weight | 166.11 g/mol |
| Purity | 97%+ |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry, keep tightly closed to prevent evaporation |
| Solubility (reference) | Soluble in methanol, ethanol, DMSO, water |
| Stability | Light-sensitive; avoid direct strong light; Hygroscopic; reseal immediately after opening; Contains ester bond; hydrolyzes under strong alkaline conditions |
| Degree of Unsaturation (DBE) | 2.0 |
| Halogen Content | F-containing |
| Nitrogen Atoms | 2 |