Suzanne Hofford, a cleanroom business manager for Contec, will be addressing sterile cleanroom products at CleanRooms Europe. CleanRooms.com recently spoke with Suzanne’s co-worker Ken O’Connor, who helped put the presentation together, to find out a little more about what will be discussed.
CleanRooms.com: What are the main points you plan to address in your presentation on sterile cleanroom products at CleanRooms Europe 2001?
Ken O’Connor: The paper will address the necessity of using sterile products in sterile (or aseptic manufacturing) processes. In the past, some companies have made do with clean, nonsterile products. This is no longer considered to be a safe or cost effective option.
Others have accepted sterilized, but unvalidated products assuming that this approach would suffice. Still other companies have opted to use in-house autoclaves to “sterilize” nonsterile products. Both approaches have been demonstrated to be deficient providing products that cannot be considered sterile.
It is obvious that products chosen for use in sterile environments must be sterile based on a sound validation protocol that tests not only the level of microbial contamination, but also the kill resistance of the microbial population. Any process or sterilization cycle that has not been developed on the basis of such a validation scheme should be deemed unreliable. In the United States, the Food and Drug Administration has recently reiterated the importance of thorough product and process validation. In particular, the FDA has always emphasized the importance of validated sterilization cycles.
CR: What would you like attendees of the presentation to walk away with?
KO: I would hope that the attendees would have a better understanding of the need for sterile cleanroom products. Although we will stress the regulatory reasons for fulfilling the validation requirements outlined by agencies such as the FDA, we will demonstrate that the use of validated sterile products makes good business sense in terms of product yields and end user safety.
As medical devices become more complex to address the opportunities of minimally invasive surgery, and as drug formulations are based on gene therapy, we expect the need for ultra clean, validated sterile products to increase.
CR: Can you explain the concept of Sterility Assurance Level (SAL)?
KO: It is not possible to determine with 100 percent certainty that a product is sterile, unless the product is tested using an accepted sterility test method. Usually, sterility tests can take up to 14 days and the entire product — or at least a representative sample — is consumed in the test. As such, the product is no longer usable at the end of the test even if the results indicate that the product is sterile. Accordingly the concept of Sterility Assurance Level or SAL was developed.
SAL is the probability that any given device or cleanroom product is sterile. The SAL is the numeric probability value that indicates how likely or unlikely it is for a particular product to be nonsterile.
The SAL is determined from the validation method used to qualify the sterilization processing cycle. The SAL is calculated by comparing the level and kill resistance of the product?s naturally occurring bioburden to a model microbial population.
For critical cleanroom products, an SAL of 10-6 is the accepted norm. At this SAL, there exists a one in a million probability that a given product is nonsterile. Other products such as gloves and garments are sometimes used at SAL’s of 10-3 or 10-4.
CR: When dealing with typical sterile products, what are the most common problems one can expect to encounter? What can be done to avoid this?
KO: In addition to the issue of proper sterilization validation, sterile products must be nonpyrogenic, nontoxic and noncytotoxic. This is particularly important for cleanroom products that may come into direct contact with drug or device products. For sterile wiper products, it is essential that nontoxic fabrics be selected and manufactured in cleanroom processes that control microbials and particulates to safe, acceptable levels.
The solvent systems used in sterile cleanroom wipers must be of the highest purity with extremely low nonvolatile residue levels. Solvent purity must be at least equal to USP requirements with semiconductor purity levels preferred.
In the past, the design of sterile product packaging has been overlooked or, at best, treated as an afterthought. As a result, it is difficult to open many of the packages used today. In fact, scissors or scalpels are required to open many packages. Such a predicament offers the very real possibility that the product could be contaminated upon removal from the package, resulting in the use of nonsterile products. To address this concern, improved packaging has been developed based upon peelable pouch and linear tear technologies to provide for safe, efficient dispensing of sterile products.
CR: What have been the biggest changes in the area of sterile cleanroom products over the last 15 years?
KO: As the cleanroom industry continues to mature, we will face increased challenges to improve product performance while controlling or decreasing costs. Performance requirements will become more stringent in proportion to the advancements in drug, device and semiconductor products. Similarly, prices for cleanroom products will parallel reductions in the biotech and semiconductor markets.
Regulatory pressures will be exerted on critical products such as those that contain hazardous chemicals. Just as we have seen in the past, there will be future requirements to develop products and packaging that can be recycled. Cleanroom companies will face continued competitive pressures as companies grow through mergers, acquisitions and consolidations.