Healthcare Volume 2 Volume Healthcare Sterilisation: Published by Smithers Rapra Technology Ltd, 2014 Challenging Practices Sterilisation: Volume 2 The collection of topics in this second volume of the book reflects challenges the reader to Challenging think beyond standard methods and question why certain current procedures remain static while technological advances abound in other aspects of sterilisation technology. By small means, better practices may come to pass to help answer some of the residual healthcare sterilisation and nosocomial infection queries: • What are some of the current challenges in healthcare sterilisation, and how can they be handled? • What are some of the acceptable current non-traditional sterilisation methods, challenging alternatives, and novel modalities? • What are some of the packaging, validation and statistical considerations of sterilisation Wayne J. Rogers practices? • How does design-of-product and packaging interrelate with sterilisation processing? Practices • Are the current sterility media and practices optimal for recovery of more modified and more resistant viable organism entities and product? • Are there increased sterility and product quality needs with new types of implantables and technological advances within the three dimensional combinations of diagnostics, drug release and challenging medical devices? Wayne J. Rogers Wayne Shawbury, Shrewsbury, Shropshire, SY4 4NR, UK Telephone: +44 (0)1939 250383 Fax: +44 (0)1939 251118 Web: www.polymer-books.com Healthcare Sterilisation: Challenging Practices Volume 2 Wayne J. Rogers A Smithers Group Company Shawbury, Shrewsbury, Shropshire, SY4 4NR, United Kingdom Telephone: +44 (0)1939 250383 Fax: +44 (0)1939 251118 http://www.polymer-books.com First Published in 2014 by Smithers Rapra Technology Ltd Shawbury, Shrewsbury, Shropshire, SY4 4NR, UK ©Smithers Information Ltd., 2014 All rights reserved. Except as permitted under current legislation no part of this publication may be photocopied, reproduced or distributed in any form or by any means or stored in a database or retrieval system, without the prior permission from the copyright holder. A catalogue record for this book is available from the British Library. Every effort has been made to contact copyright holders of any material reproduced within the text and the author and publishers apologise if any have been overlooked. ISBN: 978-1-90903-068-8 (hardback) 978-1-90903-069-5 (softback) 978-1-90903-070-1 (ebook) Typeset by Argil Services Preface Beyond the steadfast and traditional techniques of steam, dry heat and irradiation, sterilisation remains a challenge in the 21st century. Some chemical sterilisation methods such as ethylene oxide, are carcinogenic, explosive, hazardous and toxic. Non-traditional methods (e.g., hydrogen peroxide and plasma and ozone) and alternative and newer methods (chlorine dioxide, peracetic acid, hydrogen peroxide and oxides of nitrogen) have attempted to replace these dangers and hazards. They frequently have their limitations such as less penetration, adverse effects on some materials (e.g., corrosion, damage, oxidising and residuals), and some are less reliable than the steadfast and traditional methods of steam, dry heat and irradiation. Sterilisation is not a singular problem or discipline but an interfacial area of investigation of materials, biocompatibility, biocontainment, chemistry, engineering, microbiology, material, drug and patient safety, product design, statistics and validation. It requires a mulitidiciplinary effort and synergism. In parallel to these challenges, design of package, products and processing may be created that are optimal for the final sterilisation outcome(s). Optimal design, material and process development, and innovation can help to improve the current challenges of sterilisation. To achieve sterilisation without adversely affecting package and product quality and sterility, requires validation, statistics and improved scientific approaches to optimally accomplish sterility. This volume makes you question and think what you are doing in selection, design, statistics, in following standards and performing validations for sterilisation and sterile claims. iii Healthcare Sterilisation: Challenging Practices Volume 2 iv Contents 1 Traditional Chemical Sterilisation Methods ............................................... 1 1.1 Ethylene Oxide Sterilisation ........................................................... 3 1.1.1 Green sterilisation (Benefits versus Risks) .......................... 4 1.1.2 Ethylene Oxide Residuals .................................................. 8 1.1.3 Advantages of Ethylene Oxide Sterilisation ...................... 10 1.1.4 Some interdependent variables of using Ethylene Oxide... 11 1.1.5 Material Considerations with Ethylene Oxide Sterilisation ..................................................................... 13 1.1.6 Principles of Ethylene Oxide Sterilisation ......................... 14 1.1.7 Factors Affecting Lethality and Demonstrating Effectiveness .................................................................... 15 1.1.8 Microbial Effectiveness of Sterilisation ............................ 17 1.1.9 Process Variables and Types of Ethylene Oxide Sterilisation ...................................................................... 24 1.1.9.1 Process Variables................................................ 24 1.1.9.1.1 Ethylene Oxide Concentration .............. 24 1.1.9.1.2 Temperature .......................................... 25 1.1.9.1.3 Relative Humidity ................................. 25 1.1.9.1.4 Exposure ............................................... 28 1.1.10 Typical Process Sequences for Ethylene Oxide Sterilisation ...................................................................... 30 1.1.10.1 Staging ............................................................... 30 1.1.10.2 Air Removal ..................................................... 31 1.1.10.3 Typical Profile, Phases or Steps in an Ethylene Oxide Sterilisation Process ................................. 34 v Healthcare Sterilisation: Challenging Practices Volume 2 1.1.11 Some Types of Ethylene Oxide Sterilisation Cycles ......... 35 1.1.11.1 Other Ethylene Oxide Sterilisation Methods or Cycles ................................................................ 36 1.1.12 Advantages and Disadvantages of Ethylene Oxide Sterilisation ...................................................................... 38 1.1.12.1 Advantages ....................................................... 38 1.1.12.2 Disadvantages .................................................... 39 1.1.13 Recommended/Non-recommended uses of Ethylene Oxide Sterilisation .......................................................... 40 1.1.14 Some General Considerations of the Ethylene Oxide Technique ........................................................................ 41 1.1.15 Some Material Compatibility Considerations................... 42 1.1.16 Safety and Regulations for Using Ethylene Oxide ........... 44 1.1.17 Process Improvement and Enhancement .......................... 46 1.2 Glutaraldehyde (Liquid) Sterilisation ............................................ 48 1.2.1 Glutaraldehyde – A Fogging or Aerosolised Method ........ 49 1.3 Propylene Oxide ........................................................................... 50 1.4 β -Propiolactone............................................................................ 52 1.5 Glyoxal ........................................................................................ 54 1.6 Other Sterilants ............................................................................. 54 1.6.1 Chlorine Dioxide ............................................................. 54 1.6.2 Peracetic Acid .................................................................. 56 1.6.3 Hydrogen Peroxide (Liquid, Vapour, No Plasma) ............ 58 1.6.4 Methyl Bromide ............................................................... 61 1.6.5 Low Steam Formaldehyde ............................................... 62 1.7 Conclusions ................................................................................. 63 2 Traditional Liquid Chemical Sterilisation ................................................. 69 2.1 Glutaraldehyde Sterilisation ......................................................... 72 2.1.1 Characteristics of Glutaraldehyde .................................... 73 2.1.2 Properties of Glutaraldehyde ........................................... 74 vi Contents 2.1.3 Some Advantages and Disadvantages of Glutaraldehyde.. 75 2.1.4 Health Risks .................................................................... 76 2.1.5 Sterilisation and High-level Disinfection .......................... 77 2.1.6 Formulations ................................................................... 77 2.1.7 Applications and Uses ...................................................... 79 2.1.8 Glutaraldehyde within Closed Systems ............................ 80 2.1.9 Two-part Sterilisation Process using Glutaraldehyde ........ 81 2.1.10 Performance ..................................................................... 82 2.2 Chlorine Dioxide .......................................................................... 84 2.2.1 Characteristics ................................................................. 84 2.2.2 Chlorine Dioxide Solutions ............................................. 86 2.2.3 Performance ....................................................................