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A novel cleanroom apparel design incorporates modern concepts to help minimize contamination. Take a tour of the design.
In the pharmaceutical industry, the investments needed to bring a product to market are staggering. It is widely reported that the fully capitalized 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. For this reason, the US Food and Drug Administration mandates that any product that is injected, used in the eye, or used on open wounds must be sterile (i.e., free from viable microorganisms). That is because, if contaminated with microorganisms, these pharmaceutical 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 sterilized 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, is the dirtiest element in a cleanroom. Consider the following:
Keeping the operator's dirt and germs out of a sterile cleanroom environment and away from sensitive products and processes is the main objective of the sterile cleanroom suit. The suit must protect the environment from viable particles such as bacteria and yeasts and nonviable 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 entitled, "Garment Considerations for Cleanrooms and Other Controlled Environments." The recommended practice provides guidance for selecting fabric, garment construction, cleaning and maintenance of cleanroom garments, and the testing of cleanroom apparel for use in aseptic and nonaseptic cleanrooms.
Although cleanroom garments can either be disposable or reusable, according to industry analysts, most sterile facilities will opt for disposable garments because of contamination concerns relating to reusable garments returned from laundering facilities. In some companies, disposables may be used at some locations and reusables at others. The choice can depend on the classes of the various cleanrooms at various locations.
Disposable garments may be easier to manage from a cost standpoint as well, because 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, sterilization charges, and so forth.
For more than 40 years, disposable cleanroom suits have been made from flash-spun polyethylene fabric. According to industry analysts, flash-spun polyethylene provides filtration efficiency for submicron sized particles and microorganisms and is suitable for light splash protection from nonhazardous 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 sterilization cycles.
Operators in a sterile cleanroom environment in the pharmaceutical industry will wear three to four disposable suits in a day, each suit being worn for two to three hours at a time. 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 repurposed through a garment recovery service that will take the used garments and sell them back into non-sterile applications.
Cleanroom garments in the United States may be sterilized using several methods, including gamma irradiation, ebeam sterilization, and ETO sterilization. Gamma sterilization is widely considered to be the most cost-effective method. The desired sterility assurance level (SAL) for garments used in sterile pharmaceutical manufacturing is 10-6 , which translates into a one-in-a-million probability of a garment being nonsterile. 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 he or she will find something about sterile gowns that could be improved. In fact, Kimberly-Clark Professional (Dallas, TX) 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 includes the following:
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% of cleanroom operators polled during Kimberly-Clark's research report employees need to exit the cleanroom because of overheating on a regular basis.
Designing a new gowning approach
A multifunctional 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:
Sharing and evaluating the new garment and donning concepts with cleanroom operators were crucial to ensuring the new approach was successful. Testing of the Clean-Don Technology with cleanroom operators revealed the following:
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. A company must be sure to ask its garment supplier for the following:
A variety of functions will need to be involved in the approval process for a new cleanroom gown. First, safety personnel must approve the use of a new product. Each local safety officer must ensure that the product will not violate any Environmental Protection Agency (EPA) or Occupational Safety and Health Adminstration (OSHA) regulations or permits. Any changes to processes are also concerns for regulatory personnel, because they may impact the company's FDA license. After acceptance by safety and regulatory officers, quality personnel must be included and will play a key role in testing and accepting the new product or process. Quality assurance experts 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 data. The quality control organization will inspect all incoming sterile products, police the environment, and report 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 experts.
Most pharmaceutical companies 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 pharmaceutical 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 also will 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 ebeam-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 minimize the risk of contamination, it provides a strong incentive for pharmaceutical companies to consider switching.
Damon Larkin is a Product Marketing Leader, Cleanroom Apparel, at Kimberly-Clark Professional, 1400 Holcomb Bridge Road, Roswell, GA 30076, tel. 770.587.8000. firstname.lastname@example.org