Molekula
Rifaximin
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 1999 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Rifaximin is a broad-spectrum, non-absorbable antibiotic used primarily to treat gastrointestinal infections, including traveler’s diarrhea and hepatic encephalopathy. It is a rifamycin-class compound with activity against Gram-positive and Gram-negative bacteria. CAS: 80621-81-4, Molecular Formula: C43H51N3O11, Molecular Weight: 785.88 g/mol. Store at 2 to 8 °C. Signal word: Warning.
Molekula supplies Rifaximin at ≥95% purity (dried basis) in 1 g and 5 g packs, from £37.08 inc. VAT. It is in stock for same-day dispatch. Every batch ships with a certificate of analysis, and safety data sheets are available in 6 languages. Larger quantities, up to multi-tonne, are quoted on request.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
In stock — same-day dispatch
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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5 g — £93.30 per pack ex VAT · £111.96 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 | Red-orange to dark red crystalline powder |
| Heavy metals | ≤20ppm |
| Identification | Conforms to reference |
| Loss on Drying | ≤4.5% |
| Residue on Ignition | ≤0.1% |
| Assay (dried basis) | ≥95% |
| One Peak | ≤1.0% |
| Sum of Peaks | ≤3.0% |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | 2 to 8 °C |
| Transport Class | 9 |
| Packing Group | III |
| Acidity | Neutral |
Identification
| Property | Value |
|---|---|
| SKU | 71861288 |
| CAS Number | 80621-81-4 |
| IUPAC Name | [(7S,9E,11S,12R,13S,14R,15R,16R,17S,18S,19E,21Z)-2,15,17,36-tetrahydroxy-11-methoxy-3,7,12,14,16,18,22,30-octamethyl-6,23-dioxo-8,37-dioxa-24,27,33-triazahexacyclo[23.10.1.14,7.05,35.026,34.027,32]heptatriaconta-1(35),2,4,9,19,21,25(36),26(34),28,30,32-undecaen-13-yl] acetate |
| Molecular Formula | C43H51N3O11 |
| Molecular Weight | 785.88 |
| Exact Mass | 785.3524 |
| SMILES | C[C@H]1/C=C/C=C(\C(=O)NC2=C(C3=C(C4=C(C(=C3O)C)O[C@@](C4=O)(O/C=C/[C@@H]([C@H]([C@H]([C@@H]([C@@H]([C@@H]([C@H]1O)C)O)C)OC(=O)C)C)OC)C)C5=C2N6C=CC(=CC6=N5)C)O)/C |
| InChIKey | NZCRJKRKKOLAOJ-XRCRFVBUSA-N |
| InChI | InChI=1S/C43H51N3O11/c1-19-14-16-46-28(18-19)44-32-29-30-37(50)25(7)40-31(29)41(52)43(9,57-40)55-17-15-27(54-10)22(4)39(56-26(8)47)24(6)36(49)23(5)35(48)20(2)12-11-13-21(3)42(53)45-33(34(32)46)38(30)51/h11-18,20,22-24,27,35-36,39,48-51H,1-10H3,(H,45,53)/b12-11+,17-15+,21-13-/t20-,22+,23+,24+,27-,35-,36+,39+,43-/m0/s1 |
| PubChem CID | 6436173 |
| UN Number | UN3077 |
| REACH Code | Y110 |
| HTS Code | 2941903000 |
| Tariff Code | 2941900000 |
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
- H312 Harmful in contact with skin
- H332 Harmful if inhaled
- H351 Suspected of causing cancer
- H361 Suspected of damaging fertility or the unborn child
- H400 Very toxic to aquatic life
- H410 Very toxic to aquatic life with long lasting effects
Precautionary statements
- P210 Keep away from heat/sparks/open flames/hot surfaces - No smoking
- 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
- P302+352 IF ON SKIN: Wash with soap and water
- P308+313 IF exposed or concerned: Get medical advice/attention
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Portuguese, 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.
Quality certificates
Molekula Group is certified to ISO 9001:2015 (quality) and ISO 14001:2015 (environmental management), audited by a UKAS-accredited body. Both certificates are valid to 17 May 2028.
Synonyms
- Normix
- Rifacol
- Rifamycin L 105
- Rifamycin L 105SV
- Rifaxidin
- Rifaximina
- Rifaximine
- Rifaximinum
- Xifaxan
- Xifaxsan
Frequently asked questions
What is Rifaximin used for?
Rifaximin is an antibiotic used primarily for treating traveler's diarrhea and hepatic encephalopathy. It is not absorbed systemically and acts locally in the gastrointestinal tract.
What is the chemical formula and molecular weight of Rifaximin?
The chemical formula of Rifaximin is C43H51N3O11, and its molecular weight is 785.88 g/mol.
How should Rifaximin be stored?
Rifaximin should be stored at 2 to 8 °C, protected from light and moisture.
What grade of Rifaximin does Molekula supply?
Molekula supplies Rifaximin with an assay of ≥95% (dried basis), with single impurities ≤1.0% and total impurities ≤3.0%.
Can Molekula supply Rifaximin in bulk quantities?
Yes, Molekula can supply Rifaximin in bulk quantities—please contact our sales team for pricing and availability.
What documentation comes with a Rifaximin order?
Each order includes a Certificate of Analysis (CoA) and safety data sheet (SDS); additional documentation can be provided upon request.
Where can I buy Rifaximin?
Directly from Molekula, which lists Rifaximin in 1 g and 5 g packs from £37.08 inc. VAT, with a certificate of analysis for every batch. Larger quantities are quoted on request. Molekula's offices: United Kingdom, France, Spain, Germany, Italy, United States and China.
Is Rifaximin dangerous goods for shipping?
Yes. Rifaximin ships as dangerous goods: UN3077, class 9, packing group III.
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.