Aspirin Impurity 21 CAS 606-19-9
| CAS No. | 606-19-9 |
| Molecular Formula | C8H6O5 |
| Molecular Weight | 182.13 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
The occurrence of Aspirin Impurity 21 is closely related to a carboxylic acid group, a hydroxyl group, an ether linkage, an aromatic ring system in its molecular formula, which determines its behaviour during synthesis, purification, or degradation.
Aspirin Impurity 21 (CAS 606-19-9) is a certified pharmaceutical impurity reference standard with the molecular formula C8H6O5 and a molecular weight of 182.13 g/mol.
Structurally, Aspirin Impurity 21 (C8H6O5) contains a carboxylic acid group, a hydroxyl group, an ether linkage, an aromatic ring system. The molecule exhibits a degree of unsaturation (DBE) of 6.0, corresponding to approximately 6 ring(s) or double-bond equivalent(s). With a molecular weight of 182.13 g/mol, it falls into the medium-molecular-weight range. The aromatic system may exhibit native fluorescence, enabling detection with a fluorescence detector (FLD).
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.
Physical & Chemical Properties
| Molecular Formula | C8H6O5 |
| Molecular Weight | 182.13 g/mol |
| Appearance | Off-white to pale yellow crystalline powder |
| Purity | 97%+ |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry |
| Solubility (reference) | Soluble in methanol, ethanol, DMSO |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light; Hygroscopic; reseal immediately after opening |
| Degree of Unsaturation (DBE) | 6.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1957 |
Related Aspirin Standards
- Aspirin Impurity 22 (CAS 601-97-8)
- Aspirin Impurity 12 (CAS 13110-96-8)
- Aspirin Impurity 13 (CAS 57009-12-8)
- Aspirin Impurity 17 (CAS 77527-00-5)
- Aspirin Impurity 25 (CAS 38160-63-3)
- Aspirin Impurity 8 (CAS 18698-59-4)
- Aspirin Impurity A (CAS 99-96-7)
- Aspirin Impurity C / Mesalazine EP Impurity H (CAS 69-72-7)
Recommended Standards
- Salicylic Acid EP Impurity B (CAS 636-46-4)
- Mesalazine Impurity 56 (CAS CATO-C4X-132456)
- 2,3-Dinitrotoluene (CAS 602-01-7)
- Mesalazine Impurity 43 (CAS 616-79-5)
- Triptorelin Impurity 6 (CAS CATO-C4X-18626)
- Indacaterol Impurity 49 (CAS CATO-C4X-150049)
- Orforglipron Impurity 3 (CAS 2212022-55-2)
- Nafamostat Impurity 34 (CAS 19307-13-2)
- Bendamustine-D8 Hydrochloride (CAS 1134803-33-0)
- 4-Fluoro-3-nitro-5-(trifluoromethyl)benzoic acid (CAS 878572-17-9)
- 4-isopropoxy-N1,N1-dimethylisophthalamide (CAS CATO-C3D-263041)
- Cisatracurium Besilate EP Impurity R DiHCl (CAS CATO-C4X-1850112)
- Entacapone Impurity 33 (CAS 144683-49-8)
- Proinsulin C-Peptide (55-89) (human) (CAS 11097-48-6)
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