Diphenhydramine EP Impurity A HCl CAS 53499-40-4
| CAS No. | 53499-40-4 |
| Molecular Formula | C16H19NO |
| Molecular Weight | N/A |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
CATO supplies Diphenhydramine EP Impurity A HCl (CAS 53499-40-4), a pharmacopoeial impurity reference standard (molecular formula C16H19NOHCl, MW 277.79 g/mol) used for the identification and quantification of trace impurities in APIs.
Based on its molecular formula C16H19NOHCl, Diphenhydramine EP Impurity A HCl contains a nitrogen-containing heterocyclic scaffold, an amide group, a hydroxyl group, an ether linkage, chlorine substitution; these features give the compound characteristic absorption bands in UV spectroscopy. The molecular weight of 277.79 g/mol is directly relevant to the identification of the molecular ion in mass spectrometry. 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 | C16H19NO HCl |
| Molecular Weight | 277.79 g/mol |
| Purity | >95% |
| Storage | Store at 2-8°C, protect from light, keep tightly closed to prevent evaporation |
| Solubility (reference) | Soluble in chloroform, dichloromethane, ethyl acetate, DMSO |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light |
| Degree of Unsaturation (DBE) | 7.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1972 |
| Halogen Content | Cl-containing |
| Nitrogen Atoms | 1 |
Related Diphenhydramine Standards
- Diphenhydramine EP Impurity C (CAS 118-23-0)
- Diphenhydramine-d6 Hydrochloride (CAS 1189986-72-8)
- Diphenhydramine d5 Hydrochloride (CAS 1219795-16-0)
- Diphenhydramine N-Oxide(hydrochloride) (CAS 13168-00-8)
- Diphenhydramine N-Glucuronide (CAS 137908-78-2)
- Diphenhydramine Hydrochloride (CAS 147-24-0)
- Diphenhydramine impurity 18 (CAS 150556-79-9)
- Diphenhydramine EP Impurity A(Dimenhydrinate EP Impurity F) (CAS 17471-10-2)
Recommended Standards
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- 1-[4-(Diphenylmethyl)piperazin-1-yl]-2-(thiophen-2-yl)ethan-1-one (CAS 291291-92-4)
- 2,4-Dibromo-3-fluorobenzamide (CAS 1803716-05-3)
- N-(3-Phenylpropyl)-2-(3-phenylureido)thiazole-4-carboxamide (CAS 955681-43-3)
- trans-Cyclohexane-1,4-diamine (CAS 2615-25-0)
- 5-(3-(Furan-2-yl)-6-(trifluoromethyl)thieno[3,2-b]pyridin-2-yl)-4-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (CAS 400085-54-3)
- Tirzepatide Impurity 45 (CAS CATO-C4X-324045)
Why CATO?
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