Six Common Challenges in Validating Autoclaves: Ensuring Effective Sterilisation
Autoclaves play a crucial role in the pharmaceutical industry, ensuring the sterilisation of equipment, containers, and products. However, during the validation process, several common problems can be identified that may compromise the effectiveness of sterilisation. In this article, we will explore six of the most frequently identified issues when validating autoclaves and discuss strategies to address them.
Inadequate Temperature Distribution:
Proper temperature distribution within the autoclave chamber is vital for effective sterilisation. Uneven heat transfer can result in hot and cold spots, leaving certain areas of the load under-sterilised. To overcome this challenge, temperature mapping studies should be conducted to ensure uniform temperature distribution throughout the autoclave chamber. Identifying and addressing any temperature discrepancies is crucial for consistent sterilisation results.
Incorrect Load Configuration:
Autoclaves are designed to accommodate specific load configurations. Deviations from the validated conditions, such as overloading, using inappropriate containers, or incorrect orientation can prevent or restrict air removal and steam penetration, and also prevent correct condensate drainage which may result in inadequate sterilisation conditions. Validating the autoclave with specific loading configurations commonly used in the facility ensures that the sterilisation process is effective and reliable.
Inaccurate Pressure Measurement:
Accurate pressure measurement is essential for the successful operation of autoclaves. Malfunctioning or inaccurate pressure sensors can lead to incorrect measurement and control, jeopardising the sterilisation process. Regular calibration of pressure measurement devices is necessary to ensure accurate and reliable pressure readings for optimal sterilisation performance.
Improper Air Removal:
Efficient air removal is critical for achieving effective sterilisation especially in porous load autoclaves. Air pockets within the load can hinder steam penetration resulting in sub-optimal sterilising conditions. Factors such as improper loading orientation, inappropriate packaging, or leaks on the chamber and associated utilities (door gasket/air supply valve) can be factors which cause air removal to be compromised.
Failing to carry out routine engineering tests such as leak rate tests or air detector function tests and Bowie Dick tests, as well as faulty air removal monitoring devices can lead to air within the chamber not being identified. Validating air removal devices is essential to ensure correct setup of the critical device.
Wet Loads:
The presence of excessive moisture or condensation within the autoclave chamber or on the load following sterilisation of a porous load is known as a wet load. This can be caused as result of many factors including unsuitable steam supply, inadequate heat up phase, Inadequate drying phase, incorrect packaging, or loading configuration to name a few. Development studies should be carried out to ensure a robust cycle is produced which is able to meet all criteria. A dry load is imperative to ensure the sterility of the items remains following the sterilisation cycle.
Superheat:
Superheated steam is a result of the temperature of steam within the autoclave being greater than the temperature of the saturation curve. Steam that does not following the saturation curve has compromised effectivity in condensing. If steam cannot effectively condense, the latent heat cannot transfer to the items within the autoclave, therefore rendering the sterilisation process below optimal.
There are many factors which can cause superheated steam such as incorrect steam quality, incorrect supply settings, incorrect autoclave ancillaries and settings to name a few. This can result in sub-optimal sterilisation conditions and risk of unidentified non-sterile items being used in aseptic/sterile processes. Regular maintenance, calibration and validation is essential to ensure superheat does not occur and is identified if it does.
In conclusion, validating autoclaves in the pharmaceutical industry requires careful attention to various parameters to ensure effective sterilisation. Addressing common challenges such as those mentioned above, is crucial for ensuring the sterility of pharmaceutical products. Through meticulous validation studies, regular maintenance, and adherence to established procedures, autoclaves can consistently achieve reliable and effective sterilisation results.
Our team at BPV, led by our own sterilisation subject matter expert, have the skills and expertise to identify and resolve all these common problems through extensive testing which will include full root cause analysis, steam quality testing, cycle testing and development, and performance qualification. This ensures your equipment has a robust operation that produces reliable and repeatable results.
To find out more about our validation services, please contact us at [email protected]
