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Pharmaceutical Secondary Standard; Certified Reference Material

2,4-Diamino-5-(3,4,5-trimethoxybenzyl)pyrimidine, NSC 106568
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


certified reference material
pharmaceutical secondary standard


current certificate can be downloaded


HPLC: suitable
gas chromatography (GC): suitable


pharmaceutical (small molecule)



pharmacopeia traceability

traceable to BP 344
traceable to PhEur T220000
traceable to USP 1692505

storage temp.


SMILES string




InChI key


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General description

Certified pharmaceutical secondary standards for application in quality control provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to pharmacopeia primary standards. Trimethoprim is a synthetic antibacterial agent active in vitro against most aerobic gram-negative and gram-positive bacteria. Its mode of action involves inhibition of dihydrofolate reductase, an enzyme involved in catalyzing the reduction of dihydrofolate to tetrahydrofolate in both microbial and eukaryotic cells.


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.
Trimethoprim may be used as a pharmaceutical reference standard for the determination of the analyte in pharmaceutical formulations by chromatography and visible and UV spectrophotometry.
Primarily used as an antibacterial agent. Dihydrofolate reductase inhibitor with selectivity for the prokaryote enzyme.

Analysis Note

These secondary standards offer multi-traceability to the USP, EP (PhEur) 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 LRAA7172 in the slot below. This is an example certificate only and may not be the lot that you receive.


Skull and crossbonesHealth hazard

Signal Word


Hazard Statements

Hazard Classifications

Acute Tox. 3 Oral - Repr. 2

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

  1. Which document(s) contains shelf-life or expiration date information for a given product?

    If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.

  2. How do I get lot-specific information or a Certificate of Analysis?

    The lot specific COA document can be found by entering the lot number above under the "Documents" section.

  3. How do I find price and availability?

    There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers.

  4. What is the Department of Transportation shipping information for this product?

    Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product. 

  5. Is Trimethoprim stable in solution?

    Triemethoprim in a solution of 52% N,N dimethylacetamide:48% propylene glycol at 50 mg/ml is stable when stored at 25° C. There is only a 10% degradation of trimethoprim under these conditions after 885 days.

  6. My question is not addressed here, how can I contact Technical Service for assistance?

    Ask a Scientist here.

Trimethoprim resistance.
Huovinen P
Antimicrobial Agents and Chemotherapy, 31(10), 1451-1456 (1987)
Comparison of trimethoprim molecularly imprinted polymers in bulk and in sphere as the sorbent for solid-phase extraction and extraction of trimethoprim from human urine and pharmaceutical tablet and their determination by high-performance liquid chromatography
Hu SG, et al.
Analytica Chimica Acta, 537(1-2), 215-222 (2005)
Determination of sulfamethoxazole and trimethoprim in pharmaceuticals by visible and UV spectrophotometry
Shamsa F and Amani L
Iranian Journal of Pharmaceutical Research : IJPR, 537(1-2), 31-36 (2010)
Simultaneous LC determination of trimethoprim and sulphamethoxazole in pharmaceutical formulations
Akay C and Ozkan SA
Journal of Pharmaceutical and Biomedical Analysis, 30(4), 1207-1213 (2002)
J T Andersen et al.
Epidemiology and infection, 141(8), 1749-1755 (2012-09-27)
The antibiotic trimethoprim acts as a folate antagonist. Since trophoblasts are very sensitive to drugs that interfere with the folic acid cycle and thereby inhibit DNA synthesis, use of trimethoprim during the first trimester could be associated with miscarriage. A

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