Fumaric acid residue: testing mixing conditions and particle size separately

Set up the comparison

Vary mixing at one particle size, then vary size at one mixing setting. Record dissolution time, residue and temperature separately.

Measurements to record

Melting range (°C). Assess together with assay and particle size. Melting point does not establish dissolution rate in the formulation. Particle size distribution (µm or % sieve residue). State sieve opening and percentage passing. For fine or agglomerated material, specify dispersion and sieving procedures. Record the sample ID and method revision for repeat testing.

Interpreting the results

An endpoint pH reading alone cannot show whether all fumaric acid has dissolved. Inspect the residual fraction before adjusting the dose.

What to record

• Particle size
• Mixing conditions
• Water temperature
• Dissolution time
• Residue

Technical references

• ENVO: Fumaric acid product information ↗

Products and processes