The future of sterility testing

15th December 2014

Posted By Paul Boughton

Isolators remove the risk of products being contaminated by the operators conducting analysis

Parmjit S Bilan assesses whether isolator technology is the way forward for the sterility testing sector.

From a contract laboratory perspective, there are several key considerations to be discussed when choosing between an isolator and a sterility testing suite for conducting sterility testing.

Traditionally, sterility testing has been performed within a ‘Grade A’ laminar flow hood, sited in a ‘Grade B’ classified cleanroom. In contract laboratories, this type of system has worked well over the years especially because of the flexibility required with testing many different shaped and sized products, ranging from small vials to large medical devices.

However, the pharmaceutical industry and the regulatory authorities have recognised that the greatest risk of contamination of sterile products is the operators conducting the analysis.

Advances in isolator technology and tightening of regulations surrounding sterility testing have started to sway the argument in favour of isolator systems over sterility testing suites.

However, this is not a quick and easy task and choosing the right isolator can be a minefield. Choosing the wrong system can be a very expensive mistake.

The benefits of isolation

Sterility testing isolators tend to operate under positive pressure and have a ‘Grade A’ environment, and once the sample is in this area it is completely ‘isolated’ from the operator and hence from any inadvertent contamination.

A positive pressure differential between the isolator and the room environment helps add a further measure of assurance against contamination of the sample.

The quality of the environment in the room housing the isolator is of lesser significance, however it should still be able to achieve ‘Grade D’ classification or above.

An isolator that is properly designed and operated will not allow any exchange of contaminants between the room environment and itself, although minimum level of assurance is required, hence the room classification.

An isolator can be designed to fit into most types of room shapes but consideration should also be given to access to the system for routine service and cleaning as well as any additional equipment that will be housed in the room, such as a vaporised hydrogen peroxide (VHP) generator. 

Sample integrity

Although sample integrity, handling and throughput forms an obvious part of a design qualification (DQ) for an isolator, thought also needs to be given as to how the samples will enter/exit the cleanroom.

Lucideon has recently set up new pharmaceutical chemistry and microbiology laboratories. As part of its DQ the company considered a variety of aspects, which included available space, access and different designs of isolators.

The company assessed the potential types of products and the throughput of samples that it would (or wouldn’t) be able to handle. The costs of running an isolator compared to a sterility testing suite were researched, as was the overall assurance of the quality of results that would be obtained from sterility testing of products in the different environments.

How to minimise ‘false positives’ and to best assure the validity of the results obtained for the company’s customers’ sterile products was also assessed.

As a result of this work, Lucideon decided to purchase a modern isolator with a VHP system for surface disinfection – a decision set to benefit its clients greatly.

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Parmjit S Bilan is with Lucideon, in Stoke-on-Trent, UK.  





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