Expert guidance on the optimal sterilisation process

Sterile medical devices must be sterilised in a validated sterilisation process. The objective of any such process is to produce a product free of viable microorganisms. There are a variety of such sterilisation processes available, some of which are shown in Figure 1. Figure 1 shows sterilisation processes which achieve microbial inactivation by a physical process, and those that do so via the action of a microbicidal chemical agent. Physical processes can be sub-divided into those which take place at a high temperature (e.g. 121-138 °C) and those at a low temperature (room temperature to 80 °C). Processes achieving microbial inactivation using a microbicidal chemical usually employ oxidising agents such as hydrogen peroxide or alkylating agents such as EO (ethylene oxide). These processes almost invariably take place at lower temperatures (room temperature to 80 °C), and are often described as low temperature sterilisation (LTS). 

High temperature processes

In a healthcare setting, the majority (ca 90%) of reusable sterile medical devices will be sterilised at high temperatures and pressures in moist heat sterilisation processes employing saturated steam. The majority (ca 90%) of singleuse medical devices produced by the medical device industry will be sterilised in a low temperature sterilisation process, commonly using irradiation with ionising radiation (e.g. gamma), or using ethylene oxide gas sterilisation (EO). However, the industry is actively investigating alternative low temperature processes such as those employing vaporised hydrogen peroxide (VH2O2) as an alternative to EO.