How important is the selection of sterile cleanroom clothing?
People are the biggest source of potential contamination to a sterile cleanroom so sterile clothing is crucial. As a basic
requirement, sterile clothing must help maintain a cleanroom’s cleanliness while people are working in the area, by ensuring
that particle and microbiological levels are kept below the limits for the chosen grade of area, as set in the EU Guidelines
to GMP for Sterile Manufacturing. At first glance, this may seem quite straightforward. However, sterile clothing has a
direct impact on both contamination control and productivity of a sterile manufacturing process, so several factors beyond
the basic requirement need to be considered when selecting clothing.
Jaime Cassar. Cleanroom category manager at Kimberly-Clark Professional Europe
Sterile clothing should be selected with continuous improvement in mind, with choices made on the basis of either better controlling
or eliminating variables that impact contamination control and productivity. Any continuous improvement delivered by sterile
clothing will help to improve yields, and protect quality —in this way sterile clothing selection can play an important part
of a Quality by Design approach to a sterile manufacturing process. The materials, design features, manufacturing, cleaning,
packaging, sterilisation, specification, quality controls, documentation and certification of sterile clothing are all attributes
that affect how cleanroom clothing interact with sterile manufacturing processes.
How can the protection provided by sterile clothing help to create process improvements?
The cleanliness of sterile clothing is important to consider in order to prevent the clothing from itself becoming a source
of contamination. For example, sterile gloves that have been washed in di-ionised water, cleanroom packed, sterile validated
and specified for low endotoxin levels can help lower the risk of particle, microbiological and endotoxin contamination.
Sterile apparel that is laundered, cleanroom packed in individual vacuum packaging, double-bagged and provided with periodic
sterile validation will also contribute to lower contamination risks. Sterile gloves made from synthetic materials are beneficial
because they can eliminate the risk of contaminating the final product with rubber latex proteins, which can be a problem
for patients with latex allergies.
Another crucial point is the barrier performance of the clothing. Continuous improvement can come from better control or elimination
of variability in attributes that impact barrier performance. For example, disposable apparel eliminates the risk of variability
in filtration efficiency and material strength that may come from re-wearing, re-washing and re-sterilising apparel many times
and over a long period of time. Sterile apparel made from stronger materials and sterile gloves with a higher quality film
formation will be more resistant to breakage and are more likely to be free from any pinhole type defects.
As well as protecting the process from contamination, sterile clothing should also protect the wearer from the health and
safety risks presented by chemicals and APIs. Sterile gloves tested to show longer resistance times to permeation by cytotoxic
chemicals and sterile clothing certified to provide protection against chemical splashes can contribute to better protection
for the wearer. In Europe, sterile gloves and apparel should be Category III certified under the personal protective equipment
(PPE) directive 89/686/EEC, if there is risk of exposure to chemicals and APIs. There are also other ways to protect wearers
from health and safety risks. For example, sterile clothing that is biocompatible can mitigate the risk of the clothing causing
irritation to the wearer, and sterile gloves that are free from natural rubber latex will eliminate the risk of latex allergies.