Formulation-Ready Posaconazole API: Why Particle Size & Purity Matter
Formulation-Ready Posaconazole API: Critical Standards for Particle Size and Purity
Last updated: September 2026.
Posaconazole is practically insoluble in water, so dissolution, and with it bioavailability, depends on particle size and crystalline form. A formulation-ready API comes with an agreed particle size distribution (D10, D50, D90), a published impurity specification against ICH Q3A limits, and a CoA that covers residual solvents by GC. Fix PSD and polymorphic form in the purchase specification at the enquiry stage, not after the first batch.
Understanding the Critical Role of Posaconazole API
Posaconazole API (CAS 171228-49-2, C37H42F2N8O4, 700.8 g/mol) is a broad-spectrum triazole antifungal used in delayed-release tablets, oral suspensions, and injectables against invasive Aspergillus and Candida infections. It is highly lipophilic and practically insoluble in water, which is why a formulator’s first questions to a supplier are about particle size and purity, not price.
The mechanism is covered in how Posaconazole inhibits ergosterol synthesis.
Why Particle Size Matters in a Formulation-Ready API
For a poorly soluble API, dissolution rate limits absorption, and smaller particles expose more surface area to dissolve from.
The Science Behind Particle Size Distribution (PSD)
PSD is reported as D10, D50, and D90, the sizes below which 10%, 50%, and 90% of the sample volume sits. Specify all three, a D50 alone says nothing about the coarse tail that fails content uniformity or settles out of a suspension. Posaconazole is also polymorphic, and milling can change the form, so the crystalline form your dossier references belongs in the same specification.
Purity: A Non-Negotiable Parameter for Global Buyers
Four stereocentres and a multi-step route mean a batch can carry starting-material residues, process impurities, stereoisomers, and degradation products. Control of the (3R,5R) centres in the tetrahydrofuran stage decides the impurity profile. Ask any supplier, including us, how it is done.
Impurity Profile and Regulatory Standards
ICH Q3A sets reporting, identification and qualification thresholds for impurities; ICH Q3C sets residual solvent limits by class. Our published Posaconazole specification: assay by HPLC 98.0 to 102.0% w/w, total impurities not more than 1.0%, any single unspecified impurity not more than 0.1%.
Analytical Controls at Bio-Synth
Each batch ships with a CoA covering description, identification by IR and HPLC, assay, related substances, residual solvents by GC against ICH Q3C class limits, loss on drying, and residue on ignition. What changes on storage is covered in Posaconazole API impurities and stability.
Sourcing from Hyderabad: One Plant, One Quality System
We make Posaconazole API and its intermediates in-house, so the stereochemistry set early in the route and the impurities each fragment carries forward sit under one quality system. The chemistry is listed on our reaction capabilities page.
Manufacturing follows ICH Q7 principles. Our Balanagar site in Hyderabad holds a WHO-GMP certificate from the Drugs Control Administration, Telangana, valid to June 2027, and ISO 9001:2015 certification from DNV, certificate 156792-2014-AQ-IND-UKAS, first certified August 2002.
Procurement Insights: What B2B Buyers Should Look For
| Parameter | What to ask for |
|---|---|
| PSD and crystalline form | D10, D50, D90 and the polymorph in the specification, confirmed on the CoA |
| Assay and impurities | Published limits, ICH Q3A profile, ICH Q3C solvents |
| Documentation | Specification, representative CoA, stability data, regulatory file for this API |
| Supply | Lead time, campaign schedule, MOQ in writing |
A first order runs: specification and representative CoA, a sample for your own checks, a written quotation, then vendor qualification. What regulated-market buyers add is in Posaconazole API for regulated markets.
FAQs
What is the ideal particle size for formulation-ready Posaconazole API?
Micronised grades are the norm. The exact D50 and D90 depend on the dosage form and your dissolution target, so agree them in the specification.
Is micronisation mandatory for Posaconazole formulations?
Not legally, but it is technically essential for most oral products, because particle size is the main lever a formulator has over dissolution.
What documents are needed to source Posaconazole API for US and EU markets?
Specification, batch CoA, ICH Q3A impurity profile with a genotoxic impurity assessment, ICH Q3C residual solvent data, ICH Q1A stability data, a GMP certificate showing its product scope, and a DMF, ASMF, US-FDA or CEP as your market requires. The process is set out in importing Posaconazole API.
Talk to Us
Contact Bio-Synth with the crystalline form and PSD your formulation needs, and we will return a specification, representative CoA and quotation.
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