Sub-visible Particle Counting

BACKGROUND

Injections or infusions may be contaminated with mobile and undissolved extraneous particles which may then pose a danger to patients receiving the treatments.  To minimize the risk of harm to the patient, pharmacopoeias include methods for the determination of sub-visible particle counts and set limits.  At ams Laboratories particle counting is carried out using techniques that are compliant with the USP and BP/PhEur pharmacopoeias for parenteral / injectable solutions, ophthalmic solutions, medical devices and water, these include:

1. Sub-visible particle counting using a light obscuration particle counter

2. Sub-visible particle counting investigation using a light microscope

PRINCIPLE OF TESTS

1. Sub-visible particle counting using a light obscuration particle counter

This method is generally the method of choice and is carried out with the aid of a HIAC/ROYCO particle counter. It works on the principle of light blockage, which then automatically determines the size and number of particles present in a sample. 

2. Sub-visible particle counting investigation using a light microscope

The sample undergoing test is filtered and the membrane filter is manually examined under binocular microscope for any particles.

SAMPLE REQUIREMENTS

1. Container size >25 ml:  2-10 Containers
2. Container size <25 ml:  10 or more containers required to obtain a pooled volume of not less than 40mLs.
3. Medical devices for infusion: 1-10 devices, as long as the total extracted volume is < 40mLs.

    

   TEST PROTOCOLS

    

   Test description	Test code	Turnaround time
   Determination of Sub-visible Particle Counts by Light Obscuration	TMS - 001 - 01	3 days
   Determination of Sub-visible Particle Counts by Microscopy	TMS – 002 - 00	3 days