Fidaxomicin API Suppliers & Bulk Manufacturers

Available Forms: API (drug substance)

Available Strengths: Supplied to an in-house or pharmacopoeial specification

Reference Brands: Dificid, Dificlir

Category: Active Pharmaceutical Ingredient

Fidaxomicin is a narrow-spectrum macrocyclic antibiotic made by fermentation and used orally for Clostridioides difficile infection. It is sourced by formulators, CDMOs and R&D teams.

Product Description:

Fidaxomicin is a macrocyclic (macrolide-class) antibacterial produced by fermentation of the actinomycete Dactylosporangium aurantiacum. It inhibits bacterial RNA polymerase and acts mainly within the gut, with little absorbed into the bloodstream. In the US it is approved for C. difficile-associated diarrhoea in adults and children aged 6 months and older, and it is also approved in the EU for C. difficile infection (reference brands: Dificid, Dificlir).

Specification at a glance

Regulatory files and timing

The FDA list of Drug Master Files (third quarter 2026) shows 6 active Type II API DMFs for this molecule. Few filings usually means few qualified sources, so early contact with suppliers pays off. For Europe, ask whether the supplier holds a CEP or an EU ASMF and, for imports into the EU, a written confirmation.

Generic or biosimilar entry. United States: Generics/biosimilars on the market (Jul 2025). European Union: No confirmed date.

Handling and quality points

As a fermentation product, fidaxomicin comes with a family of closely related natural analogues, so the specification needs limits for named related substances and a method that separates them. Ask about the producing strain, the purification steps and the solid form, as these shape the impurity and stability profile. The usual fermentation documentation applies, including residual solvents from extraction and TSE statements for any animal-derived raw materials.

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Brand names are trademarks of their respective owners and identify the reference medicine only. Information is general and was checked in October 2026; confirm specifications and filings with the supplier before purchase.