Damon Larkin, Product Marketing Leader, Cleanroom Apparel, Kimberly-Clark Professional, in this article addresses the importance of process protection in cleanrooms via the appropriate cleanroom suit. It provides an overview of the sterile cleanroom apparel category and defines key areas for improvement. Also, it introduces a new concept for sterile cleanroom gowning to help minimise the problems associated with current technologies
In the pharmaceutical industry, the investments needed to bring a product to market are staggering. In fact, it is widely reported that the fully capitalised cost to develop a new drug can range from $800 million to nearly $900 million. The steep price of product rejects and recalls makes it crucial to ensure high product yields by maintaining strict cleanroom cleanliness and sterility. That is one of the reasons that the US Federal Drug Administration (FDA) mandates that any product that is injected, or used in the eyes or on open wounds must be sterile, i.e., free from viable microorganisms. That is because, if contaminated with microorganisms, these pharma products can adversely harm patients.
Microorganisms introduced into a cleanroom environment need only three things to grow: moisture, food and temperature – all of which exist in a cleanroom. Consequently, all incoming air, water, chemicals, and materials must be filtered or sterilised to meet high standards of purity and microbiological control, so as not to contaminate processes or products in production. Also to be ‘filtered,’ in a sense, is the cleanroom operator, who, most will agree, is the dirtiest thing to enter a cleanroom.
Consider the following
Keeping the operator’s dirt and germs out of the sterile cleanroom environment and away from sensitive products and processes is the main objective of the sterile cleanroom suit. The suit needs to protect the environment from viable particles such as bacteria and yeasts, and non-viable particles such as hair, dead skin cells, and dandruff. To that end, it is critical for cleanroom operators to select cleanroom suits that provide not only the highest levels of inherent sterility, but also the greatest chances of maintaining that sterility through the gowning process.
Sterile cleanroom suits: An overview
Although there are no federal regulations for sterile cleanroom garments used in the pharmaceutical industry, guidance for the industry is available from The Institute of Environmental Sciences and Technology (IEST), which publishes a recommended practice IEST-RP-CC003.3, “Garment Considerations for Cleanrooms and Other Controlled Environments.” The recommended practice provides guidance for the selection of fabric, garment construction, cleaning and maintenance of cleanroom garments and testing of cleanroom apparel for use in aseptic and non-aseptic cleanrooms.
While cleanroom garments can either be disposable or reusable, according to industry analysts, most sterile facilities will opt for disposable garments due to contamination concerns relating to reusable garments returned from laundering facilities. In some companies, disposables may be used at some locations and reusables at others. This can depend on the classes of the various cleanrooms at different locations. Disposable garments may be easier to manage from a cost standpoint as well, since the price for reusable garments often carry ‘hidden’ charges such as delivery and pick-up fees (and related energy surcharges), lost/unused garment charges, laundering and sterilisation charges, and more.
For the past 40+ years, disposable cleanroom suits have been made from flashspun polyethylene fabric. According to industry analysts, flash-spun polyethylene provides filtration efficiency for sub-micron sized particles and microorganisms and is suitable for light splash protection from non-hazardous liquids.
Disposable suits also can be made from spunbond-meltblown-spunbond (SMS) fabric, which has outer layers of spunbond polypropylene for strength and cloth-like comfort, with middle layers composed of a matrix of microfibers, which creates a torturous path for fine particles and liquids.
Reusable cleanroom suits are typically made from woven polyester-blend fabrics, which may degrade after multiple laundering and sterilisation cycles. Most operators in a sterile cleanroom environment in the pharma industry will wear three to four disposable suits in a day, each suit being worn for two to three hours at a time. Often, cleanroom protocol dictates that garment changes must be made each time the cleanroom is re-entered. Once discarded, these suits can be incinerated, or they can be re-purposed through a garment recovery service that will take the used garments and sell them back into non-sterile applications.
Cleanroom garments in the US may be sterilised via several methods, including gamma irradiation, e-beam sterilization and ETO sterilisation. Gamma sterilisation is widely considered to be the most cost-effective method. The desired Sterility Assurance Level (SAL) for garments to be used in sterile pharma manufacturing is 10-6, which translates into a one-in-a-million probability of a garment being non-sterile. Once sterile, cleanroom suits must be packaged in a way that this sterility is maintained throughout handling, transportation and storage.
Sterile gowning: Room for improvement
Ask any cleanroom operator and chances are that he or she will find something about sterile gowns that could be improved. In fact, Kimberly-Clark Professional did just that, spending the better part of two years interviewing cleanroom operators, visiting them in their workplaces and evaluating the features and functions of traditional sterile cleanroom gowns to identify areas in which there was potential room for improvement.
Key findings of that research
The issue of garment comfort was also addressed. Scientific research in the workplace has revealed that a moderate variation in body temperature can greatly reduce concentration and increase risk-inducing behavior. Workers unable to maintain a thermo-neutral zone, or comfort zone, have a higher tendency to become injured and need time off from work, thus reducing productivity. In fact, more than 40 per cent of cleanroom operators polled during Kimberly-Clark’s research report employees need to exit the cleanroom due to overheating on a regular basis.
Inside R&D: Designing a new gowning approach A multi-functional product development team at Kimberly-Clark Professional set out to design a new approach to sterile gowning that would eliminate the problems identified during the company’s research.
The resulting Clean-Don Technology provides the following features:
Validation and training: Inculcating the new approach One of the necessary steps when validating a new sterile cleanroom gown is to carefully review the garment’s certification.
Certificates of conformance
These verify that a specific product lot conforms to all specifications before the lot is released. Physical characteristics should be tested in accordance with relevant ASTM standards. Particles should be tested in accordance with relevant IEST standards.
Certificates of irradiation
These document the minimum and maximum dosage of irradiation that a product received. Look for sterilisation validation documentation that confirms that the doses have been verified, the loading patterns were sufficient, and that the process is audited on a regular basis.
A variety of functions will need to be involved in the approval process for a new cleanroom gown. First, safety must approve the use of a new product. Each local safety officer must ensure that the product will not violate any EPA or OSHA regulations or permits. Any changes to processes are also concerns for regulatory personnel, as they may impact the company’s FDA license. After acceptance by safety and regulatory, Quality must be included and will play a key role in testing and accepting the new product or process. Quality assurance personnel are involved in reviewing all of the procedures and process records, testing the product to ensure its sterility, and approving the final selection based on the data. The Quality Control organisation will inspect all incoming sterile products, policing the environment and reporting the result. The purchasing department is the final step in the process and often provides rubber-stamp approval for ordering the products already accepted by the other players.
Most pharma companies will conduct a new garment validation process for three to nine months, during which time the new garments would be worn in a controlled area, though not necessarily in the actual cleanroom in which the garment is designed to be worn.
In many pharma companies, a new sterile gown also will need to undergo testing on three lots before validating and approving it. In some cases, a change to the standards of practice for that environment will also be required. Many users will assess a garment’s sterility on-site by using contact plates or swabs containing a nutrient media. To formally validate gamma- or e-beam-irradiated garments for sterility assurance levels, use ANSI/AAMI/ISO 1137-1994 ‘Sterilization of Health Care Products – Requirements for Validation and Routine Control – Radiation Sterilization’ and ANSI/AAMI/ISO 11737-1-1995 “Sterilization of Medical Devices –Microbiological Methods – Part 1: Estimation of Population of Microorganisms on Products.”
Validating a new sterile cleanroom garment is not a task to be undertaken lightly. However, when a new approach to sterile gowning can help improve the gowning process, reduce opportunities for operator error, and minimise the risk of contamination, it provides a strong incentive for pharma companies to consider switching.
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