White Paper on sterilisation technologies expected

PDA reveals ongoing discussions on indirect product contact surfaces

An important addition to accepted sterilisation technologies for indirect product contact surfaces will be published in a White Paper later this month.

Experts revealed ongoing discussions with European Health Authorities and the US FDA during the recent PDA Conference.

A recurrent problem is the transfer of equipment and material into Restricted Access Barrier Systems (RABS). Equipment, such as a stopper bowl used in an aseptic manufacturing process and operated in a RABS, needs to be sterile to prevent it contaminating product. Today, such indirect contact parts surface sterilisation is frequently performed outside the RABS and hence aseptic transfer of bulky and/or heavy equipment into the system presents a risk. If this operation could be performed in place, it would reduce the contamination risk.

“As contact between, for example, a stopper bowl and the product would be indirect, industry experts have suggested the use of automated gaseous, vapour phase, decontamination processes have a place between traditional sterilisation and disinfection,” said James Drinkwater, process director of Bioquell and chairman of PHSS.

“In discussions with MHRA (UK) and FDA (US) representatives, we have put forward hard data and justification, that indirect product contact surfaces can be surface sterilised in place using an automated gaseous, vapour phase, decontamination process resulting in a 6 log sporicidal reduction that can easily be designed to create an overkill situation. If the gaseous decontamination is also used for non-contact parts then 4 log sporicidal reduction may be acceptable, if followed and supported by a thorough risk assessment.”

Today the benchmark for an automated decontamination process suitable for Gassing-in-place (GIP) indirect product contact surfaces is hydrogen peroxide vapour. As a process that can be validated to achieve conditions of surface sterilisation there are important prerequisites of bioburden characterisation and validation of cleaning residues to ensure there is not a potential for cleaning and peroxide compounds that may be a chemical contamination to the product via indirect mechanical transfer. Stainless steel is a mild catalyst to hydrogen peroxide, so peroxide will not exist on the surface but can compound with other chemical residues if present.

Drinkwater said White Paper would be published shortly and a Technical Monograph most probably in October.

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