Medical Device Link.

MANUFACTURING

Guidance on sterility assurance levels

In view of the dramatic increase in the number of complex medical devices that contain a drug or other biologically active component, researchers need to consider sterilisation earlier in the development process. At the iiA sponsored workshop held in conjunction with IMRP 2008, speaker Bob Morrissey (The Wiscasset Group, USA) announced that he and six other experts are to study the issue of sterility assurance levels (SALs) with the aim of developing practical guidance that has international agreement. This task force group is made up of US and European experts, including Professor Alan Tallentire (Air Dispersions, Manchester, UK) and Eamonn Hoxey (Johnson and Johnson, Bracknell, UK). The US Food and Drug Administration and the Centre For Disease Control and Prevention have agreed to participate.

Championed by iiA and supported by the Advancement of Medical Instrumentation (AAMI), Morrissey and John Masefield (STERIS Isomedix,Mentor, Ohio, USA) have led the move towards developing rational methods for selecting SALs to facilitate the selection of minimum radiation doses that will render products safe for their intended use in the patient. A study was conducted by iiA to determine if AAMI Working Group 90 should undertake a revision of ST 67, Sterilisation of Health Care Products, Requirements For Products Labeled STERILE. It showed wide support from industry, academia and government for a scientific approach to the selection of the SAL for combination health care products. Specifically, 118 (80%) of the 147 respondents indicated that their current radiation sterilisation requirements would benefit from a wider dose range and the establishment of lower minimum doses. Of the respondents, 94% support the new work item on SALs and 89% support efforts for it to become a global standard. AAMI adopted this new work item in June 2008 and met to further discuss it on 9 December 2008 in Washington, District of Columbia, USA.

“Regulators, when comparing aseptic processing with terminal sterilisation are saying terminal sterilisation is preferred wherever possible,” Masefield said. “This is because it lowers the chance of error and risk of a contaminated product causing infection or transmitting a disease to the patient. The aim is to select the appropriate SAL and radiation sterilisation dose, but manufacturers are warned by Morrissey that this will entail additional testing and validation.

Information supplied by Ruth Brinston Manager, International Irradiation Association, Ottawa, Canada, rbrinston@iiaglobal.org