Entecavir Impurity 57 CAS 84868-56-4

Purity 97%+In StockPharmacopoeial Impurity Standards
CAS No.84868-56-4
Molecular FormulaC21H20O2
Molecular Weight304.38 g/mol
CategoryPharmacopoeial Impurity Standards / EP Impurities
AvailabilityIn Stock

Chemical Structure

Entecavir Impurity 57 CAS 84868-56-4 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.

Entecavir Impurity 57 (CAS 84868-56-4) is a certified pharmaceutical impurity reference standard with the molecular formula C21H20O2 and a molecular weight of 304.38 g/mol.

Structurally, Entecavir Impurity 57 (C21H20O2) contains a steroid core, a hydroxyl group, an ether linkage. The molecule exhibits a degree of unsaturation (DBE) of 12.0, corresponding to approximately 12 ring(s) or double-bond equivalent(s). With a molecular weight of 304.38 g/mol, it falls into the moderately-high-molecular-weight range. The high carbon-to-hydrogen ratio imparts good lipophilicity, allowing liquid-liquid extraction with non-polar solvents such as n-hexane or ethyl acetate.

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 FormulaC21H20O2
Molecular Weight304.38 g/mol
AppearancePale yellow to yellow crystalline powder
Purity97%+
StorageStore at 2-8°C, protect from light
Solubility (reference)Soluble in chloroform, dichloromethane, ethyl acetate, DMSO
StabilityMay oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light
Degree of Unsaturation (DBE)12.0
UV AbsorptionUV-absorbing
Structural FeaturesAromatic ring present
CAS Registry Year (est.)1981

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