Methotrexate Impurity 28 CAS 5939-37-7
| CAS No. | 5939-37-7 |
| Molecular Formula | C20H22N8O6 |
| Molecular Weight | 470.44 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
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.
As a process- or degradation-related impurity, Methotrexate Impurity 28 (CAS 5939-37-7, C20H22N8O6) is essential for impurity profiling, related-substances testing, and forced-degradation studies in pharmaceutical development.
Owing to a flavonoid core, an amide group, a hydroxyl group, an ether linkage, Methotrexate Impurity 28 is typically pale yellow to yellow crystalline powder. Its solid-state physicochemical attributes — including a molecular weight of 470.44 g/mol — guide the selection of appropriate sample preparation and analytical techniques. The aromatic system may exhibit native fluorescence, enabling detection with a fluorescence detector (FLD).
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 | C20H22N8O6 |
| Molecular Weight | 470.44 g/mol |
| Appearance | Pale yellow to yellow crystalline powder |
| Purity | >95% |
| Storage | Store in a cool place (≤25°C), protect from light, keep sealed and dry |
| Solubility (reference) | Soluble in DMSO, DMF, methanol |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light; Hygroscopic; reseal immediately after opening |
| Degree of Unsaturation (DBE) | 14.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1958 |
| Nitrogen Atoms | 8 |
Related Methotrexate Standards
- Methotrexate EP Impurity H (CAS 67022-39-3)
- Methotrexate EP Impurity I (CAS 66147-29-3)
- Methotrexate Impurity 18 (CAS CATO-C4X-115418)
- Methotrexate Dimethylamide (CAS 71074-44-7)
- Methotrexate impurity N3 (CAS 65148-64-3)
- Methotrexate EP Impurity J (CAS 34378-65-9)
- Methotrexate Impurity 61 (CAS 65148-63-2)
- Methotrexate-d3 (CAS 432545-63-6)
Recommended Standards
- 4-({[(4-chlorophenyl)methyl]sulfanyl}methyl)-6-[(4-chlorophenyl)sulfanyl]-2-(pyridin-2-yl)pyrimidine (CAS 338960-88-6)
- R406(free base) (CAS 841290-80-0)
- 2-Bromo-6-(dihexylamino)anthracene-9,10-dione (CAS 919992-00-0)
- N-(2-((4-(Bis(2-chloroethyl)amino)phenyl)thio)ethyl)acridin-9-amine (CAS 130031-48-0)
- Ilaprazole Impurity 145 (CAS 67382-06-3)
- Etoricoxib Impurity 86 (CAS CATO-C4X-108086)
- Atosiban Impurity 4 (CAS 2381861-04-5)
- 1-(2-Chloro-3-fluorophenyl)-2,2,2-trifluoroethan-1-ol (CAS 2228943-38-0)
- 4-Methoxy-3-((2-methylthiazol-4-yl)methoxy)benzaldehyde (CAS 923819-76-5)
- 477762-45-1 8-[(E)-2-[1-(4-fluorophenyl)ethylidene]hydrazin-1-yl]quinoline hydrochloride 8P-859 (CAS 477762-45-1)
- 7-(Benzo[d][1,3]dioxol-5-yl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile (CAS 685106-66-5)
- Phenyl 2-Ethylbutanoate (CAS 54897-51-7)
- Methyl 2-acetamido-4-bromo-5-chlorobenzoate (CAS 2655726-96-6)
- Acetyl Tetrapeptide- 15 (CAS 928007-64-1)
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