Cleaning cleanrooms

Abstract

Cleanroom cleaning requires many specialised products. Dr Tim Sandle, head of microbiology, Bio Products Laboratory, addresses the importance of product selection and cleaning techniques in the pharmaceutical manufacturing environment.

Suitable disinfectants, such as this sterile spray from schuelke, must be manufactured under clean conditions, with the quality assessed through appropriate manufacturing techniques and held in appropriate packaging.

Cleanroom cleaning requires many specialised products. Dr Tim Sandle, head of microbiology, Bio Products Laboratory, addresses the importance of product selection and cleaning techniques in the pharmaceutical manufacturing environment

Pharmaceutical manufacturing takes place within a series of specially controlled environments – cleanrooms. On one level, a cleanroom or clean zone is simply an area that is clean in terms of both particle counts (as defined in the international cleanroom standard ISO14644) and microbial counts (as defined in a second cleanroom standard for biocontamination control, ISO14698.¹ In addition, regulatory requirements for cleanrooms are detailed by EU GMP or the FDA guidelines.

One important step towards achieving microbial control within a cleanroom is the use of defined cleaning techniques, together with the application of detergents and disinfectants. The detergents and disinfectants used in pharmaceutical grade cleanrooms need to be of a high quality and effective at killing micro-organisms. Both correct product selection and cleaning techiques are important, particularly in relation to some of the newer cleanroom technologies.

Cleaning agent selection: The types of detergents and disinfectants used represent an important decision for the pharmaceutical manufacturer. There are various different types of disinfectant with different spectrums of activity and modes of action.²

Disinfectants have differing efficacies. Some are bacteriostatic, where the ability of the bacterial population to grow is halted. Here, the disinfectant can cause selective and reversible changes to cells by interacting with nucleic acids, inhibiting enzymes or permeating into the cell wall. Once the disinfectant is removed from contact with bacteria cells, the surviving bacterial population could potentially grow.

Other disinfectants are bactericidal in that they destroy bacterial cells through different mechanisms, including: causing structural damage to the cell; autolysis; cell lysis and the leakage or coagulation of cytoplasm. Within these groupings the spectrum of activity varies, with some disinfectants being effective against vegetative Gram positive and Gram negative micro-organisms only, while others are effective against fungi. Some disinfectants are sporicidal in that they can cause the destruction of endospore forming bacteria.

Pharmaceutical manufacturers are expected to use at least two disinfectants of different modes of activity in order to conform with current Good Manufacturing Practices.³ The use of a sporicidal disinfectant is recommended for sterile areas on an occasional basis, even where such a disinfectant does not form part of the standard set. When selecting disinfectants, it is prudent to opt for manufacturers who offer a range of disinfectants of different modes of activity (which target and kill microbial cells in different ways).