Sterilisation Methods

This chapter discusses methods and equipment for the sterilisation of medicinal products, medical devices, and utensils. Sterilisation is an active, validated process to kill microorganisms. It is a critical step in the preparation of sterile products. The achievement of the absolute state of sterility cannot be demonstrated, sterility can be defined only in terms of probability. Classical sterilisation techniques using an autoclave and saturated steam under pressure, hot water or dry heat are practical and reliable. Other reliable sterilisation methods include membrane filtration, ionising radiation sterilisation (gamma and electron-beam radiation) and gas sterilisation (ethylene oxide, formaldehyde). Sterilisation equipment (autoclaves, membrane filters, and other sterilisers) is often used in industrial manufacturing, in preparation in pharmacies, and in other healthcare establishments. Standard sterilisation processes are described in the Ph. Eur., in other current Pharmacopoeias, in ISO standards and National guidelines. The efficacy of any sterilisation process depends on the nature of the product and container, the extent and type of any contamination before sterilisation, the production and sterilisation conditions. Pre-cleaning of materials and pre-filtration by membrane filtration result in a low bioburden. Process validation, quality assurance and quality control are important to ensure sterility.