Understanding the hydrogen peroxide vapour sanitisation process and introducing the MCHP concept, a personal account
This article traces the history of hydrogen peroxide vapour as used for sanitising pharmaceutical isolators and similar volumes. From an early puzzle as to how the vapour could be so effective in deactivating resistant test organisms, the author moves forward through his own career to develop a clearer comprehension of the hydrogen peroxide vapour process. The term “micro-condensed hydrogen peroxide” (MCHP) is introduced as an aid to understanding how the process truly acts and this understanding helps to generate robust sanitisation cycles. This new knowledge can be applied to the many devices becoming commercially available for sanitising isolators.
It is now more than 30 years since I first encountered gas phase sanitisation as applied to pharmaceutical isolators. This was in the form of the old MAN peracetic acid vaporiser produced by the French company La Calhene (now Getinge La Calhene). It immediately struck me as remarkable that the vapour generated from a 3.5% solution of peracetic acid could be so effective in killing off micro-organisms. How could a mere gas, with concentrations of just 0.1% (which is the result of warming a 3.5% solution), act so quickly to inactivate the very
resistant spores of an organism like G. Stearothermophilus?
Moving on, when I formed Cambridge Isolation Technology (CIT), I became involved in the development of a gas generator to supersede the MAN, working with a combination of 10% hydrogen peroxide and 1% peracetic acid that we named “Citanox”. In theory, the new “Citomat” gas generator and Citanox should have easily out performed the MAN in terms of time to achieve kill, but it did not always do so. On some occasions the test Biological Indicators (BIs) would be completely deactivated, while at other times, with exactly the same operating parameters, there were many survivors. I could find no obvious explanation for this unpredictable behaviour. […]
A courtesy of ‘Clean Air & Containment Review’ – www.cleanairandcontainment.com
- author: Tim Coles