Levothyroxine Impurity 37 CAS 94345-95-6
| CAS No. | 94345-95-6 |
| Molecular Formula | C16H15I2NO4 |
| Molecular Weight | 539.10 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
Levothyroxine Impurity 37 (CAS 94345-95-6) is a certified pharmaceutical impurity reference standard with the molecular formula C16H15I2NO4 and a molecular weight of 539.10 g/mol.
Based on its molecular formula C16H15I2NO4, Levothyroxine Impurity 37 contains a flavonoid core, an amide group, a hydroxyl group, an ether linkage, iodine substitution; these features give the compound characteristic absorption bands in UV spectroscopy. The molecular weight of 539.10 g/mol is directly relevant to the identification of the molecular ion in mass spectrometry. Nitrogen-containing functional groups confer excellent ionization efficiency in positive-ion electrospray (ESI) mode, making the compound well suited to LC-MS/MS analysis.
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 | C16H15I2NO4 |
| Molecular Weight | 539.10 g/mol |
| Appearance | Pale yellow to yellow crystalline powder. (slight halide-like odor, low volatility) |
| 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.) | 1983 |
| Halogen Content | I-containing |
| Nitrogen Atoms | 1 |
Related Levothyroxine Standards
- Levothyroxine Impurity 16 (CAS 4192-14-7)
- rac-Levothyroxine EP Impurity J (3,3'-DL-Diiodothyronine) (CAS 70-40-6)
- Levothyroxine EP Impurity J (CAS 4604-41-5)
- Levothyroxine EP Impurity E (CAS 1041-01-6)
- Levothyroxine Impurity 18 (CAS 1155-40-4)
- Levothyroxine Impurity 58 (CAS 176258-87-0)
- Levothyroxine Impurity 38 (CAS 1027-28-7)
- Levothyroxine Impurity 42 (CAS 4618-45-5)
Recommended Standards
- (S)-Methyl 2-amino-3-(4-(4-hydroxyphenoxy)-3,5-diiodophenyl)propanoate (CAS 203585-45-9)
- N-(2-Hydroxyethyl)perfluoro(2,5-dimethyl-3,6-dioxanonan)amide (CAS 137506-19-5)
- 5-(3-Chlorophenoxy)-N1,N1,N3,N3-tetraphenylbenzene-1,3-diamine (CAS 2252518-02-6)
- Bromo(triphenylphosphine)gold (CAS 14243-65-3)
- Tenofovir disoproxil Impurity 144 (CAS CATO-C4X-1076144)
- Buspirone EP Impurity C HCl (CAS CATO-C4X-125819)
- Phloroglucinol Impurity 69 (CAS 53254-99-2)
- Gefitinib Impurity 21 HCl (CAS 184475-68-1)
- Ac-Ala-Ser-Thr-Asp-AMC (I-1785.0005) (CAS 354151-60-3)
- 3-(2-Methoxy-4'-(methoxycarbonyl)-[1,1'-biphenyl]-4-yl)propanoic acid (CAS 406233-39-4)
- 1-Chloro-3-(2-methoxyethoxy)-2-methylpropane (CAS 1341685-97-9)
- 1-(2,7-diazaspiro[3.5]nonan-2-yl)ethanone;hydrochloride (CAS 2227205-94-7)
- 5-bromo-1H-indazol-7-amine (CAS 316810-86-3)
- Exenatide Acetate (CAS 141732-76-5)
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