Inspectors of the British Medicines and Healthcare products Regulatory Agency (MHRA) publish their views on different topics in various blogs. In this way, Andrew Hopkins - among others chairperson of the working group for the revision of Annex 1 - published his opinion on decontamination of isolators by means of vapour hydrogen peroxide.
The use of isolators in sterile manufacturing is getting ever greater. Compared to the production in classic sterile rooms, isolators offer a significantly higher level of contamination control. This higher level of contamination control is an aspect which is now pointed out in almost all regulations.
Isolators themselves have to be decontaminated prior to their use. Because of their dimensions, classic sterilisation procedures (dry or moist heat / irradiation) cannot be used. Decontamination by means of vapour hydrogen peroxide has thus emerged as the alternative method. Although this process can achieve a high elimination rate of bio indicators, it is subject to a few uncertainties.
How to deal with direct or indirect product contact parts? Do they have to undergo decontamination with vapour hydrogen peroxide when installed or do those parts have to be sterilised - as far as feasible - and after sterilisation be installed in the isolator?
According to Andrew Hopkins' expectations, both direct and indirect contact parts have to be sterilised using a "robust" sterilisation method. Andrew Hopkins interprets robust sterilisation as
Those sterilised parts shouldn't be exposed to the isolator environment until the decontamination cycle is completed.
Andrew Hopkins doesn't commit himself to 100% to these expectations. Yet, he concedes that in the course of a risk-oriented observation also other approaches can be achieved. He rather expects from companies considering a different approach to sterilisation to seek a dialogue with the agency at an early stage.
For further information please see the Andrew Hopkin's entry in the MHRA Blog entitled VHP (Vapour Hydrogen Peroxide) Fragility.