Molekula
Trimethoprim
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 2000 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Trimethoprim is a synthetic antibacterial agent used primarily in combination with sulfamethoxazole to treat bacterial infections. It is also the active ingredient in veterinary antimicrobial medicines. It functions by inhibiting bacterial dihydrofolate reductase, disrupting folate metabolism. Available as a white to off-white crystalline powder, it has a CAS number of 738-70-5, molecular formula C14H18N4O3, and molecular weight of 290.32 g/mol. Store at 2 to 8 °C. Hazard classification includes signal word Danger. Molekula supplies Trimethoprim from research to bulk quantities with full documentation and ISO 9001:2015 traceability.
Example image for illustration only. Other packaging and pack sizes are available.
Often bought together
Pricing & pack sizes
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
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1 g — £30.90 per pack ex VAT · £37.08 inc. VAT
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25 g — £135.60 per pack ex VAT · £162.72 inc. VAT
Need a different quantity or pack?
Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
Prices exclude VAT/sales tax and shipping.
Specifications
| Property | Value |
|---|---|
| Appearance | A white or yellowish-white powder |
| Melting Point | 199 - 203°C |
| Heavy metals | ≤20ppm |
| Loss on Drying | ≤1.0% |
| Solubility | Very slightly soluble in water, slightly soluble in alcohol, practically insoluble in ether |
| Assay | 98.5 - 101% |
| Sulphated Ash | ≤0.1% |
| Related Substances | ≤0.2% |
| Appearance of Solution | Not more intensely colored than reference solution BY7 |
| Identification (IR) | In accordance with the spectrum of trimethoprim EPCRS |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | 2 to 8 °C |
| Transport Class | 9 |
| Packing Group | III |
| Acidity | Neutral |
Literature values
Published physical properties of the substance, not batch specifications.
| Property | Value |
|---|---|
| Appearance | White to cream, crystalline powder |
| Odour | Odorless |
| Melting Point | 199 - 203 °C |
| Water Solubility | 400 mg/L at 25 °C |
| Solubility (other solvents) | Very slightly soluble in water and slightly soluble in alcohol |
| pKa | pKa = 7.12 (at 20 °C) |
| log P (octanol/water) | 0.91 |
Source: PubChem CID 5578 (HSDB, Human Metabolome Database (HMDB), DrugBank)
Identification
| Property | Value |
|---|---|
| SKU | 20124481 |
| CAS Number | 738-70-5 |
| IUPAC Name | 5-[(3,4,5-trimethoxyphenyl)methyl]pyrimidine-2,4-diamine |
| EC Number | 212-006-2 |
| Molecular Formula | C14H18N4O3 |
| Molecular Weight | 290.32 |
| Exact Mass | 290.1379 |
| SMILES | COC1=CC(=CC(=C1OC)OC)CC2=CN=C(N=C2N)N |
| InChIKey | IEDVJHCEMCRBQM-UHFFFAOYSA-N |
| InChI | InChI=1S/C14H18N4O3/c1-19-10-5-8(6-11(20-2)12(10)21-3)4-9-7-17-14(16)18-13(9)15/h5-7H,4H2,1-3H3,(H4,15,16,17,18) |
| PubChem CID | 5578 |
| UN Number | UN3077 |
| REACH Code | Y110 |
| HTS Code | 29335995 |
| Tariff Code | 2933599590 |
Safety & GHS
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Health Hazard
GHS07
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Serious Health Hazard
GHS08
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Hazardous to the Environment
GHS09
Hazard statements
- H302 Harmful if swallowed
- H361d Suspected of damaging fertility. Suspected of damaging the unborn child.
- H373 May cause damage to organs through prolonged or repeated exposure
- H411 Toxic to aquatic life with long lasting effects
Precautionary statements
- P260 Do not breathe dust/fume/gas/mist/vapours/spray
- P273 Avoid release to the environment
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P301+312 IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell
- P308+313 IF exposed or concerned: Get medical advice/attention
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Spanish.
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Synonyms
- 2,4-Diamino-5-(3,4,5-trimethoxybenzyl)pyrimidine
- Monoprim
- Monotrim
- Proloprim
- Syraprim
- Trimetoprim
- Trimopan
- Trimpex
- Uretrim
- Wellcoprim
Frequently asked questions
What is Trimethoprim used for?
Trimethoprim is an antibiotic used to treat bacterial infections such as urinary tract infections, bronchitis, and ear infections by inhibiting bacterial dihydrofolate reductase.
What is the chemical formula and molecular weight of Trimethoprim?
The chemical formula is C14H18N4O3 and the molecular weight is 290.32 g/mol.
How should Trimethoprim be stored?
Trimethoprim should be stored at 2 to 8 °C, protected from light and moisture.
What grade of Trimethoprim does Molekula supply?
Molekula supplies Trimethoprim in research-grade purity, suitable for laboratory use.
Can Molekula supply Trimethoprim in bulk quantities?
Yes, Molekula can supply Trimethoprim in bulk quantities—please contact our sales team for pricing and availability.
What documentation comes with a Trimethoprim order?
Each order includes a Certificate of Analysis (CoA) and Safety Data Sheet (SDS); additional documentation can be provided upon request.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.