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Orphenadrine Citrate

Pharmaceutical Secondary Standard; Certified Reference Material

Orphenadrine citrate salt, o-Methyldiphenhydramine citrate salt, β-Dimethylaminoethyl 2-methylbenzhydryl ether citrate salt
Empirical Formula (Hill Notation):
C18H23NO · C6H8O7
CAS Number:
Molecular Weight:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


certified reference material
pharmaceutical secondary standard


current certificate can be downloaded


pkg of 1 g


HPLC: suitable
gas chromatography (GC): suitable


pharmaceutical (small molecule)



pharmacopeia traceability

traceable to PhEur Y0000101
traceable to USP 1479009

storage temp.


SMILES string




InChI key


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General description

Pharmaceutical secondary standards for application in quality control, provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards.
Orphenadrine Citrate is an analog of diphenhydramine antihistamine drug. It operates as a centrally acting skeletal muscle relaxant and effectively serves to relieve painful skeletal muscle spasms by working as an analgesics.


These Secondary Standards are qualified as Certified Reference Materials. These are suitable for use in several analytical applications including but not limited to pharma release testing, pharma method development for qualitative and quantitative analyses, food and beverage quality control testing, and other calibration requirements.
Orphenadrine Citrate may be used as a pharmaceutical reference standard for the determination of the analyte in pharmaceutical formulations by chromatography as well as spectrophotometry techniques.

Biochem/physiol Actions

Muscarinic receptor antagonist; H1 histamine receptor antagonist; muscle relaxant. Orphenadrine has also been reported to inhibit the noradrenergic transporter and to block the NMDA receptor ion channel.

Analysis Note

These secondary standards offer multi-traceability to the USP, EP and BP primary standards, where they are available.

Other Notes

This Certified Reference Material (CRM) is produced and certified in accordance with ISO 17034 and ISO/IEC 17025. All information regarding the use of this CRM can be found on the certificate of analysis.


To see an example of a Certificate of Analysis for this material enter LRAA8433 in the Documents slot below. This is an example certificate only and may not be the lot that you receive.


Skull and crossbones

Signal Word


Hazard Statements

Hazard Classifications

Acute Tox. 3 Oral

Storage Class Code

6.1C - Combustible, acute toxic Cat.3 / toxic compounds or compounds which causing chronic effects



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis

Certificate of Origin

Development of a capillary electrophoresis method for the determination of orphenadrine citrate in tablets in the presence of paracetamol.
Haj-Ali DN and Hamdan II
Saudi Pharmaceutical Journal : SPJ : The Official Publication of the Saudi Pharmaceutical Society, 18(4), 233-237 (2010)
Spectrophotometric determination of phenylephrine HCl and orphenadrine citrate in pure and in dosage forms.
Shama SA
Journal of Pharmaceutical and Biomedical Analysis, 30(4), 1385-1392 (2002)
Khaled Darwish et al.
Chemical & pharmaceutical bulletin, 60(11), 1426-1436 (2012-11-06)
New, simple, rapid and precise reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of orphenadrine citrate, caffeine and aspirin in presence of aspirin degradation products, orphenadrine citrate and caffeine process related impurities, and excipients. Good resolution and

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