| Tim Sandle at Bio Products Laboratory evaluates the validation of active air-sampling
Environmental monitoring is a programme which evaluates the cleanliness of the manufacturing environment; the effectiveness of cleaning and disinfection programmes; and the operational performance of environmental controls. As such, pharmaceutical manufacturers of both sterile and non-sterile products, as well as medical devices, are required to demonstrate that manufacturing processes and procedures minimise any potential contamination to the product from the manufacturing environment. Contamination can arise from a number of sources: water, air, surfaces and personnel, each of which poses a potential risk to product.
Each microbiological environmental monitoring method requires validation in order to show its suitability within the cleanroom environment. Due to the importance placed on environmental monitoring data, the results which the manufacturer obtains must be reproducible and assure that the aseptic environment or trends within non-sterile manufacturing are under control. Arguably, now more than ever, environmental data is scrutinised during FDA CGMP and pre-approval new drug inspections – this trend is likely to continue. This reproducibility can be established through method validation.
Although standard environmental test methods have been in existence for years and are accepted throughout the industry, they do not necessarily yield reproducible results. One type of culture media used in conjunction with one type of air-sampler in a particular facility will behave very differently to another. In addition, new test methodologies must be validated to be as good as, or better, than the methods they are replacing. This makes at least some validation of monitoring methods essential.
This article examines the validation of one aspect of microbiological monitoring: active air-sampling. Air-sampling is important as the air in most manufacturing areas is microbiologically contaminated, although the level will vary: an office will be considerably more contaminated when compared to a Grade B cleanroom. Whilst air is a vector of micro-organisms, it is not a nutritive environment. Therefore, many micro-organisms in the air die from desiccation or photosensitivity. Many other micro-organisms are anaerobic and thus will not survive or will be unable to multiply. However, microorganisms may be able to settle onto critical surfaces. As much of the risk centres on air velocities and air flows, the use of active volumetric air-samplers is important. |
