Levothyroxine EP Impurity B CAS 1628720-66-0
| CAS No. | 1628720-66-0 |
| Molecular Formula | C15H11ClI3NO4 |
| Molecular Weight | 685.42 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
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.
Levothyroxine EP Impurity B (CAS 1628720-66-0) is a certified pharmaceutical impurity reference standard with the molecular formula C15H11ClI3NO4 and a molecular weight of 685.42 g/mol.
Structurally, Levothyroxine EP Impurity B (C15H11ClI3NO4) contains a flavonoid core, an amide group, a hydroxyl group, an ether linkage, chlorine/iodine substitution. The molecule exhibits a degree of unsaturation (DBE) of 9.0, corresponding to approximately 9 ring(s) or double-bond equivalent(s). With a molecular weight of 685.42 g/mol, it falls into the high-molecular-weight range. Halogen substitution (F/Cl/Br/I) produces a distinctive isotope pattern in mass spectrometry, a valuable aid for qualitative confirmation.
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.
Physical & Chemical Properties
| Molecular Formula | C15H11ClI3NO4 |
| Molecular Weight | 685.42 g/mol |
| Purity | >95% |
| Storage | Store at room temperature, protect from light, keep sealed and dry |
| Solubility (reference) | Soluble in methanol, acetonitrile, DMSO, water (slightly soluble) |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light; Contains ester bond; hydrolyzes under strong alkaline conditions |
| Degree of Unsaturation (DBE) | 9.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1993 |
| Halogen Content | Cl/I-containing |
| Nitrogen Atoms | 1 |
Related Levothyroxine Standards
- Levothyroxine Impurity 25 (CAS CATO-C4X-167825)
- Levothyroxine Impurity 15 (CAS CATO-C4X-167815)
- Levothyroxine EP Impurity I (CAS 2016-06-0)
- Levothyroxine Impurity 44 (CAS 176258-89-2)
- Levothyroxine Impurity 41 (CAS 2055-94-9)
- Levothyroxine EP Impurity A (CAS 6893-02-3)
- Levothyroxine EP Impurity K (CAS 5817-39-0)
- Levothyroxine EP Impurity K (R-Isomer) (CAS 66701-15-3)
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