skip to content

Sub-visible Particle Counting

We carry out particle counting using a variety of techniques that are compliant with the USP, EP and JP as well as to client specifications and ISO standards, typically for the enumeration of sub-visible contaminant particles in parenteral/injectible solutions, ophthalmic solutions and water.

Sub Visible Particle CountingAnalysis includes:

  • Sub-visible particle counting using the light obscuration particle count tests
  • Sub-visible particle count investigation using the microscopic particle count test

These methods are used:

  • As quality control in batch preparations during development or prior to release
  • To monitor filtering efficiency
  • To monitor particles shed from product components and surgical implants



Sub-visible Particle Counting Using A Light Obscuration Particle Counter

  • Traceable particle count standards are run once per week to ensure accurate results
  • Testing is carried out in a laminar flow cabinet
  • Permissible for size range 2 µm - 125 µm @ various integers i.e. 2, 5, 10, 15, 25 mm etc.; currently calibrated to 80 µm (can be extended)

Sub-visible Particle Counting Using Light Microscopy For Investigational Projects (based upon USP <788>/PhEur (2.9.19))

  • Preparation is carried out in a laminar flow cabinet
  • This method allows a visual assessment of precipitates and particulates in a solution, with the option of photographic evidence of the observations

Visible Particle Assessment Carried Out In Accordance With PhEur (2.9.20)

  • An estimation of visible particles present in small volume liquid parenterals.
  • A brief description of observed particles e.g. colour, shape and an estimation of size.

Back to top