Pharmaceutical Division Microbiology

Sterility Testing

The sterility test can be applied to any substance, preparation or article that according to the Pharmacopoeia is sterile.

The principle is that the testing looks for both aerobic and anerobic contamination of  the product undergoing the sterility test.

The sterility test at ILS is performed under aseptic conditions in an
ISO 14644-1 Class 5 clean room.

Two sterility methods are employed at ILS.

Membrane filtration - Sterility Test

In this procedure the product if filtered or the device is rinsed, and the rinse liquid passed through a membrane filter. Any microbial cells are retained by the filter. Differant filtration units are used for differing products.

With membrane filtration there are more manipulations than direct inoculation and ILS uses a closed proprietory system that reduces contaminations risks.

This method also allows for products that have inhibitory factors to be sterility tested as rinses can be used to negate the inhibitory effects.

The filter is then placed into media selected to encourage growth of any accompanying bacteria or fungi.

ILS use Tryptone Soya Broth and Fluid Thioglycollate for sterility testing.

The media is then incubated at the appropriate temperature for a total of 14 days.

Direct inoculation - Sterility Test 
 

This method is only used when membrane filtration is not possible the sample is inoculated directly into the media or the device is placed directly into the media.

 
Microbial contamination of the test area is assessed throughout the duration of the sterility test, by means of air sampling, settle, contact plates and personnel plates.

ILS produces and quality controls all of the media used for sterility testing and the media production faciltiy is UKAS accredited.

Products that ILS have assessed for Sterility Include;

• Drugs
• Cytotoxic Products
• Chemotherapy Agents
• Eye Drops
• Allergens
• Medical Dressings - Bandages
• Medical Devices - Bone Cement Mixing Devices

 Contact ILS - for any further information or prices on sterility testing