Selecting and Validating Aqueous Detergents

Malcolm C. McLaughlin
May 1999
Today, the terms "critical" or "precision" cleaning are used interchangeably to refer to any cleaning process in which residue can cause a failure in the function of the surface being cleaned. In that regard, there is perhaps no more demanding application for cleaning than pharmaceutical manufacturing, where solids and liquids come into contact with plastic, glass, and metal piping and processing equipment, and where cross-contamination can be costly, in terms of both lost product and risk to human and animal health. Many leading drug companies, as well as firms that manufacture medical devices, are finding that aqueous cleaners provide the scrupulous cleaning required for manufacturing healthcare related products. Examples:
Capsules and tablets. Some pharmaceutical ingredients resist going into solution, making tablet presses and dies difficult to clean. Even stubborn, sustained-release product residues come clean quickly with appropriate aqueous cleaners.
Suspensions. Aqueous cleaners also eliminate intensive scrubbing and human contact in cleaning large stainless steel tanks as much as 2000 gal. used in manufacturing liquid suspensions.
Intermediates. Aqueous cleaners are suitable for cleaning glass-lined chemical reactors used in processing pharmaceutical intermediates such as powders, fillers, binding agents, and other chemicals. Aqueous cleaners are synthetic detergent cleaning agents used in a water solution. The chemical and mechanical action involved includes a number of processes: Solubilization increases the solubility of a substance in a particular medium.
Wetting lowers surface and interfacial tensions so that the cleaner penetrates small spaces while getting under the soil to lift it from the substrate.
Emulsification creates an oil/water mixture by coating oil droplets with surfactant to keep them from recombining and migrating to the surface of a cleaning bath.
Deflocculation prevents agglomeration by breaking soil into fine particles and dispersing them through the cleaning medium.
Sequestration is the reaction with ions such as calcium, magnesium, or heavy metals to prevent the formation of insoluble byproducts (such as soap scum).
Saponification is the alkaline hydrolysis of fat by the reaction of fatty acids with alkalies to form water-soluble soaps. The following reviews the principal components of aqueous critical cleaners, considerations for their selection, and methods of pharmaceutical validation of their use.
Components of Aqueous Cleaners
Water, the "universal solvent," is an important basic component of aqueous cleaners because it dissolves many types of soils. Water--which may be municipal tap water, well water, deionized, or distilled water, depending on the cleaning application--also functions as a carrying medium for detergent compounds. Water is a polar solvent that is good at dissolving a wide range of polar soils.
Water has a unique "V" shaped structure with two hydrogen atoms at the top of the "V" and an oxygen at the bottom. This directional shape towards the base of the "V" is called a dipole moment. Polar molecules such as water have a dipole moment. This dipole moment is important because it allows stable solutions of other dissolved polar-soil molecules to become arranged in more thermodynamically stable alternating positive and negative ends of molecules.
In addition to having a desirable dipole moment that helps dissolve other polar soils, water is capable of bonding to soils by a mechanism called hydrogen bonding. The ability of water to undergo hydrogen bonding is relatively unique among solvents. This capability gives water significant additional ability to dissolve soils as compared with other solvents. But while water is capable of dissolving many inorganic and some organic contaminants, not all soils dissolve readily in water. For this reason, aqueous detergent cleaners are complex mixtures specifically formulated to create greater chemical and mechanical cleaning action with ingredients that enhance the ability of water to hold soils. Typically these include surface-active agents (surfactants) and builders, which react with dissolved metal ions in the water to help stop them from interfering with cleaning.
It is critical that the detergent be able to clean effectively and to rinse away without leaving interfering residues and a scientifically formulated detergent will also typically include nondepositing rinse-aids. And since corrosion is the enemy of high-quality metal parts, corrosion inhibitors are often used in aqueous-cleaning formulations.
Detergent Selection
The major variables in cleaning using aqueous methods include the following:
Cleaner. The cleaner or detergent used should be matched to the desired cleaning method, and the surface and types of soils being cleaned. For instance, a low-foaming detergent should be used for spray or machine cleaning; a good anti-redeposition detergent for soak and ultrasonic cleaning; and a high emulsifying and wetting detergent for manual cleaning. The detergent, temperature, and degree of agitation should be strong enough to remove the soil to the desired level of cleanliness without harming the substrate being cleaned.
Agitation. Agitation can be none (as in soaking), or be performed manually (with a cloth, sponge, brush), ultrasonically, via flow-through clean-in-place (for pipes, tanks, and tubes), spray cleaning (clean-in-place spray balls), and high-pressure spray cleaning. In general, the more agitation, the more effective the cleaning on bulk soils. Cleaning can often be enhanced by pre-soaking, particularly if soils are dried or baked onto the part to be cleaned. It is always desirable, whenever possible, to clean prior to soils becoming dried or baked onto surfaces.
Temperature. In general, higher-temperature cleaning solutions result in better cleaning. In practice, there is typically an optimum temperature for a given combination of cleaning variables. Many soak, manual, and ultrasonic cleaning methods work best, for example, at 50-55¡C. Many spray washing techniques work best at 60-70ºC. Waxy or oily soils are more easily cleaned at somewhat higher temperatures. Particulate soils tend to be more easily cleaned at slightly lower temperatures.
Cleaning time. As a rule, the longer the cleaning time, the more thorough the cleaning. Many cleaning mechanisms-such as emulsifying, dissolving, suspending, and penetrating-are time-dependent. Up to the point where cleaning has been completed, the longer they're employed, the more cleaning is accomplished. Cleaning time can be accelerated by increased agitation, the use of more aggressive detergents, and by increasing temperature. If you cannot increase agitation, detergent, or temperature, then you must be prepared to use longer cleaning times to achieve the desired cleanliness. (There are some instances when long cleaning times may promote substrate corrosion, weakening, or swelling.)
Type of rinse. A thorough rinse will remove soils which have been cleaned from the surface and any residue from the detergent itself. Whatever contaminants are present in the rinse water can also be present after rinsing. Therefore, in pharmaceutical process equipment and medical device cleaning, high-purity rinse water is required.
Drying method. Drying can affect residues and corrosion since impurities from rinse water can be deposited during evaporation. Water, particularly high purity rinse water, can be corrosive to metal substrates during heated and air drying. The use of physical water removal drying techniques can help minimize such corrosion. It is also important to keep in mind that a cleaner's pH value can have a direct effect on cleaning effectiveness and each detergent formulation has maximum effectiveness at a specific pH value. An acidic cleaner would be effective for removing insoluble metal salts such as those used in time release coatings. Alkaline (basic) cleaners can be formulated to remove organic soils. Enzyme cleaners can be highly effective on protein soils. Alkaline cleaners work best when the soil can be hydrolyzed (typically natural oils and fats, fingerprints, natural greases, some types of pharmaceuticals, and protein residues). The cleaning process should be enclosed to avoid exposure hazards. Most cleaners are alkaline in nature since hydrolysis--and the chelation and dispersing of soils-typically occurs most effectively at alkaline pH levels. However, the higher the pH the more corrosive the cleaner.
Other Factors
It is important to select detergents for testing that are manufactured with appropriate quality-control procedures, with lot-number tracking and certificates of analysis from the manufacturer. These certificates document each lot of detergent to assure consistency and quality control from lot to lot in order to control for potential cleaning failure due to inconsistencies in manufacturing or unannounced formulation changes. It is desirable to choose a detergent from a manufacturer that maintains quality control on their raw materials and in turn keeps retained samples of each lot of detergent that is used to be able to respond to concerns about a particular batch. The detergent should be widely available and economical to use (for optimum economy, a concentrated detergent is typically used at 1:100 to 2:100 dilutions). The detergent concentrate should be diluted according to the manufacturer's instructions; typically, warm (about 50 degrees C) or hot (about 60 degrees C) water is used. Ambient temperature water may be acceptable, especially with presoaking. For difficult soils, very hot water should be used (>65 degrees C), and the recommended detergent concentration doubled.
Validation
In pharmaceutical manufacturing of human and animal health products, acceptable levels of residues must be carefully calculated. This is accomplished using a variation of the "Lilly Calculation," which involves determining a maximum dosage of the ingredient, the number of doses per volume of process equipment, and the surface area of that equipment: Maximum Residue= (maximum dose X number of doses in equipment) /surface area of equipment (Maximum dose is the highest amount to which a person can effectably be exposed--e.g., three logs below the LD50 of the compound.)
In practice, analytical methods can detect well below calculated maximum residues. The acceptable detection limits for a detergent are usually set well below, since the pharmaceutically active ingredients of a medicine will usually require much higher levels of cleanliness.
If 10 L of rinse water were used to extract the 100 L tank, then a rinse water residue of 10 ppm (100 mg/10 L) would correspond to 7 mg/square centimeter (100 mg/14,000 square centimeter). This is way below the typical calculated numbers.
There are a number of ways to analyze such residue based on the brand of detergent, including anionic surfactant analysis, direct UV/Visible determination, high performance liquid chromatography (HPLC), atomic absorption (AA) or inorganic residues, and liquid chromatography (LC), phosphate detection, protease enzyme detection, and total organic carbon (TOC). Detergent suppliers should be able to provide information on residue detection.
When rinsing with deionized water, conductivity has been used to detect conductive salts. Standard solutions of known dilution should be made up to determine the detection limits. There are two basic types of tests:
Rinse water test. Test a parameter of the rinsewater before and after rinsing the surface. No significant change in the parameter measured indicates no detected residue.
Wipe or swab test. Wipe a known area of the surface you wish to test with a clean swab or filter paper that is soaked with extraction solution such as 50/50 isopropanol/high purity water. Digest or extract the swab or filter paper and analyze for residue. Use glass fiber filter paper or swab for extraction methods. Do not use isopropanol mixtures for UV or TOC detection methods.
By choosing an appropriate cleaning method, detergent, and approach to residue detection, aqueous cleaners can be effectively used for cleaning pharmaceutical process equipment and medical devices.

Tutorial On HEPA Filtration

By: Jason Kelly
March 2007


HEPA filters are used in cleanrooms in many different industries, including semiconductor, pharmaceutical medical devices, nuclear, and biotechnology. The main function of a HEPA filter is to provide clean air to the cleanroom. The HEPA filter is constructed with many pleated layers of filter media paper; this design prevents particles from freely passing through the filter as they become trapped and stick onto the filter fibers (Figure 1). There are four mechanisms at work: capture by straining, impaction, interception, and diffusion (Figure 2). Straining/sieving is defined as when a particle is too large and becomes trapped between two filter fibers. Impaction is when a particle of relatively greater mass is unable to follow the curved streamline around the fiber and, as a result of momentum, travels in a straight line into the filter fiber and sticks. Interception occurs when a section of a particle “runs into” a filter fiber. Diffusion capture occurs when particles leave the streamline due to random collisions with the surrounding fluid molecules and strike the fibers, where they again stick.
LEAK TESTING
ISO 14644-2 outlines the frequency of cleanroom validation according to cleanroom classification. Part of this validation includes leak testing of the HEPA filter. ISO 14644-3 outlines the testing procedure to follow.
EQUIPMENT REQUIRED
Aerosol Generator: used to produce an aerosol upstream of the HEPA filter. A stable test aerosol has particles that have the following distribution:

• More than 20% by mass of particles less than 0.5 µm
• More than 50% by mass of particles less than 0.7 µm
• More than 75% by mass of particles less than 1.0 µm

An annual output test should be carried out to verify that the aerosol meets this distribution.
Photometer: used to measure the upstream aerosol concentration and downstream penetration of the HEPA filter by the aerosol; it should be calibrated at least annually.
Particle Counter: used to measure the concentrations of particles of different sizes downstream of the HEPA filter; it should be calibrated at least annually.

Figure 1: Filter media magnification x500

Figure 2: Filter mechanisms at work

AEROSOL GENERATOR OUTPUT TEST
The aerosol generator output test, carried out annually by the supplier, verifies that the aerosol generator is capable of producing a stable distribution. The photometer verifies that the sensor/optics and flow rates are within tolerances. Some new digital photometers now on the market have the ability to verify on “power up” the condition of the sensor/optics and flow rates as part of a self-diagnostics program and, therefore, improves the reliability of the unit continually instead of waiting annually for the calibration and hoping it passes. Photometer operators can be satisfied that the photometer is free from contamination around the sensor/optics, the flow path is unobstructed, the unit is performing correctly, and that the results are accurate.
TEST METHOD
A linear photometer may be used to measure upstream concentrations provided it is calibrated.
This upstream concentration may be used as the 100% reference, enabling percentage penetration downstream to be measured directly. The linear photometer may be used to test filters to 0.01%.
TEST REQUIREMENTS
Each filter requires an upstream challenge of 20–100 µg/L for best results. One must find the area of the filter and the airflow through the filter before calculating the throughput of the filter. The product of throughput and concentration are required to give the aerosol output required. Alternatively, the aerosol can be adjusted to reference the photometer at 100%.
TEST PROCEDURE
Disperse the test aerosol upstream of the HEPA filter to produce a uniform challenge concentration in the region of 20–100 µg/L. Using the photometer, measure the upstream challenge concentration.
Maintain this concentration throughout the test. Adjust the aerosol generator such that the challenge concentration at the upstream filter face is at a level such that the photometer can be set and maintained at a stable reading of 100%. The photometer is then set at 100%.
Using the same photometer, scan the entirety of the downstream face and perimeter inclusive of the sealing device with the sampling probe. Hold the probe approx 25 mm away from the area tested and pass over the entire area in slightly overlapping strokes, at a rate of 5 cm/sec. Record the location of any steady, repeatable reading of the photometer that exceeds 0.01% for grades A through D in the relevant class of environmental cleanliness. Refer to ISO 14644-3 section B.6.2.5 for a more detailed procedure.
GUIDELINES
Care should be taken when generating the upstream aerosol as too much aerosol will over-concentrate the filter and filter replacement will be necessary; use too little aerosol and there may be insufficient aerosol to effectively scan the filter sufficiently. Discuss these scenarios with to reach an agreement regarding the upstream concentration.
Once a leak has been detected, repair of the filter will be necessary, following the manufacturer’s procedure regarding the type of repair media and guidelines on resealing the filter and performing tests after the repair. After successful testing, a particle counter positioned under the filter can evaluate the condition of the filter and can be used as a back up to the photometer.
References

• ISO 14644-3
• ISO 14644-2
• IEST-RP-CC034
• IEST-RP-CC007

Jason Kelly is the Director of OptiCal Sciences,Ireland Ltd.and has been working in the semiconductor and pharmaceutical/medical device cleanroom industry for the last ten years.He can be reached at www.optical-sciences.ie.

FDA Regulation of Software for Medical Device Manufacturers

David A Vogel, PH.D.
June 2005
WHILE THE DIZZYING ARRAY of FDA regulations and changes may seem overwhelming, there is a checklist that can help you stay sane and in compliance.
Medical device manufacturers are regulated in two different but related ways by the FDA. First as with drugs, device manufacturers must convince the FDA through a pre-market notification process that their devices are both safe and effective. However, the FDA also requires medical device manufacturers to comply with its Quality System Regulations (QSRs). This set of regulations controls the methodologies and processes used by a manufacturer to design, develop, manufacture, and maintain their devices. This second set of controls is intended to assure the quality and consistency of the development and manufacturing processes by requiring a formal, systematic quality system to further assure the safety of the device.
Software gets special attention from the FDA. Software is now embedded in a large percentage of electro-medical devices, and the amount of device functionality controlled by software is continually growing. Software controls many medical device manufacturers’ design, development, manufacturing, and quality processes, regardless of whether software is a part of the manufactured device or not. Software failures can often be invisible and difficult to detect, and they can thus have disastrous consequences on the operation or quality of medical devices. For this reason, the FDA specifically requires validation of both device software and quality-system software.
There is a notion in the industry that compliance with FDA regulations is difficult because the “rules are constantly changing.” To some extent this is true, especially as they relate to software. Understanding why the rules appear to change can help medical device manufacturers cope with and even predict future changes.
Just What Are the “Rules”?
It is important to have an understanding that there are different types of “rules” that originate from different sources and that require different levels of compliance from device manufacturers. It’s useful to think of the hierarchy of rules as a tree. The root structure of the tree is federal law, in this case the Food, Drug, and Cosmetics Act of 1938, which was amended in 1976 and most recently revised in 1997. As you can see, this is not a rapid rate of change. The roots of our “rules-tree” do not move much in response to short-term influences. One unfortunate, related fact is that legislative change usually only takes place after a well publicized, large-scale tragedy.
The trunk of our rules-tree is the FDA’s Code of Federal Regulations (21 CFR 800-1299). Compliance with these regulations is mandatory, as is compliance with the legislation mentioned above.
The FDA’s guidelines for complying with its regulations are published as guidance documents, represented as the main branches off the trunk of the rules-tree. Compliance with the guidance documents is voluntary, although any deviation from the guidances should be explained and defended by the device manufacturer. Guidance documents are updated approximately every five years, and new guidances are issued as the need arises (more on this later). The roots and trunk of our rules-tree are very stable and resist movement as the winds of technology change rush by. The guidance branches, however, do tend to sway a bit as technology changes.
The twigs and leaves of the rules-tree are the industry standards and industry technical information reports (TIRs). These are usually written by industry consensus and organized by industry associations, often with FDA participation. Compliance is voluntary. These rules fluctuate as often as a group volunteers to write or rewrite them. Often they are written around a process or technique that is in vogue at the time. The TIRs are usually written as survey reports on a number of applicable methodologies in use that are applicable to a regulated activity. They are not at all proscriptive and as such are weaker documents than standards. In other words, TIRs neither recommend nor outlaw activities; they only present alternative ways to approach a problem. The twigs and leaves of the rules-tree branch sprout and change relatively rapidly as the winds of technology change and personal opinion and industry preference whistle through them.
Good Reasons for the Rules to Change
Now that we have an understanding of the relative rates of change of the various types of rules, let’s examine what stimulates the changes.
The original Food, Drug, and Cosmetics Act of 1938 became legislation after nearly 100 people died from ingesting an elixir containing a substance similar to antifreeze. The FDA’s power to require pre-market notification (PMN) wasn’t granted until the Medical Device Amendments of 1976, prompted by the injuries of thousands of women by the Dalkon shield intrauterine device. The massive X-ray overdose of cancer patients in the Therac-25 incident of the 1980s was caused by a software error and led to the Safe Medical Device Act of 1990 and the subsequent publication of the FDA’s QSRs in 1996, which gave software special attention. In all these cases, it was catastrophe that stimulated changes in legislation and regulation.
Change also breeds change. The QSRs mention the validation of software as a regulatory requirement. This new requirement led to the publication of the FDA Guidance on the General Principles of Software Validation (GPSV). Although it was a technology change (introduction of software into medical devices) that led to the software validation requirements in the regulation, it was the regulatory change itself that created the need for compliance guidelines.
Technology change stimulates change in the regulatory environment. Much of the regulation and guidance available from the FDA today related to software development and software validation implicitly assumes a lifecycle model roughly equivalent to a waterfall model or modified waterfall model. A waterfall lifecycle is one that sequentially goes through well-defined phases such as Concept, Specification, Design, Implementation, Test, and Maintenance. Today’s “agile methods” such as “extreme programming” do not fit well into the existing guidelines on software validation. If and when agile methods gain in popularity in the medical device industry, we can expect the guidelines to evolve to clarify the regulatory intent for this group of developers. As a second example, consider programmable parts such as field programmable gate arrays (FPGAs). The GPSV is targeted for software in general-purpose PCs and embedded microprocessors; it is seldom applied to software in other programmable parts such as FPGAs. As more functionality migrates to these types of devices, there is increased likelihood of catastrophic failure and subsequent updated regulatory guidance.
Evolution of regulatory thought is also responsible for some regulatory change. As device companies attempt to comply with the regulations and guidelines, it becomes evident that some guidelines work better than others. As TIR workgroups meet to discuss different ways to comply with FDA regulations, they question all aspects of the regulations and guidelines, and recommend change. As the industry strives to achieve compliance, tools evolve to help automate regulatory tasks and make possible other actions not originally anticipated by the regulators. All of these reasons and many others lead to evolution in the thought behind the regulations and ultimately to the evolution of the regulations and guidelines themselves.
Sometimes the Rules Don’t Change But Seem To…
There is another phenomenon that gives the impression that the FDA’s rules are always changing. This has to do with the logistics of enforcement of the rules.
Even when legislation, regulations, and guidelines are not changing, there will always be a spectrum of interpretation and opinion within the FDA. Consequently, the FDA response to submissions might vary from examiner to examiner. The results of manufacturer inspections will also vary among FDA inspectors. Interpretation and opinion accounts for some of the differences, but so do level of training, years of experience, and aptitude for the job. This level of variation exists even when there are no changes in the written rules.
Now consider what happens when the FDA’s regulations or guidelines do change. The entire examiner and inspector workforces need to be retrained on the new regulations, guidelines, or policies. This process itself can take months or years. During the training period there will be an obvious imbalance in application of the rules in addition to the variations already mentioned above.
To further complicate matters, as individual documents evolve within regulatory structure, the changes are likely to contradict or otherwise conflict with other, older documents in the regulatory tree. This can lead to confusion within the medical device industry as well as within the regulatory agency itself. This is an unfortunate byproduct of an agency tasked with trying to regulate an industry that changes rapidly with evolving medical science and device technology.
How Can Medical Device Manufacturers Deal with the Regulatory Realities?
It might at first seem like a hopeless cause to keep a medical device company in compliance given the challenges noted above. It can indeed feel hopeless if one gets lost in the apparent problems with the process and misses the big picture. Keep in mind that the FDA’s primary concern is to assure the public that medical devices are safe and effective. That’s the “Big Picture.”
There are a number of things you can do to stay as close to compliance with the regulations as possible:
Know what rules apply to your company, and to your specific area of responsibility. The sections of the Federal Regulations of most applicability to medical device manufacturers are 21 CFR 820 (the Quality System Regulations), and 21 CFR 11 (a.k.a. Part 11 – Electronic Records and Electronic Signatures).

• Never assume that the regulations don’t apply to your situation because your company is small, or has a small budget, or doesn’t have the expertise available.
• Always do something to respond to each of the regulatory requirements. You can always debate the adequacy of what you’ve done, but you can seldom defend doing nothing.
• Always document your response to each regulatory requirement. In the eyes of an inspector or auditor, if you didn’t document it, you didn’t do it.
• Always take the time to understand why the regulators might feel each requirement is important for device quality and respond to that requirement appropriately. It does little to improve or assure the quality of a device when you take shortcuts in the quality process just to satisfy regulatory requirements
• Never document that your company has followed a process required by regulation when you really have not. Inspectors are trained to find evidence of this kind of activity. Furthermore, this deceptive activity does nothing to add value or quality to your device.
• When in doubt about how to comply with regulations, do the right thing. The most defensible position always will be that which does the most to assure the safety and effectiveness of the device.

Regulations of Particular Interest to Manufacturing and Process Engineers
The software validation requirements that apply to software used in manufacturing and process control are regulated by 21 CFR 820.70 and 21 CFR 820.30. All software, from machine-tool embedded software, to materials-planning software, to simple spreadsheets, is subject to these regulations.
The FDA, in collaboration with the Association for the Advancement of Medical Instrumentation (AAMI), has met with industry representatives for the past two years to produce a TIR on the Validation of Regulated Quality System Software. This workgroup’s research has identified a number of categories of software. These categories include off-the-shelf software, configurable or customizable off-the-shelf software, programmable software (e.g. macro-driven software), and totally custom-developed software.
There is a regulatory requirement to validate all of these types of software for their intended use. Yet there are very different levels of knowledge and control that a device manufacturer has over these very different categories of software. Consequently the validation needs to be handled in different ways.
The TIR will explain the differences in detail, propose a number of different methodologies for determining what level of validation is required, suggest a number of validation activities, and offer examples of how various types of software can be validated.
By understanding and keeping up with FDA software regulation, medical device manufacturers can hit the “moving target” of the latest FDA rules and requirements. Doing so enables the production of the best possible products with the fewest possible compliance snafus.
David A. Vogel, Ph.D., is president of Intertech Engineering Associates, Inc., 249 Vanderbilt Ave., Norwood, MA 02062. He can be reached at 781-255-5420 or dav@inea.com.

Changing from Disposable to Reusable

Jan Eudy
November 2004
Of all of the components that comprise cleanroom operations and processes, humans are the easiest to control, yet contribute the most contamination.
Over the years the contamination control industry has evolved unique, innovative fabrics and apparel to encapsulate humans working in the cleanrooms thereby protecting the product and the processes from possible deleterious contamination.
Historically, cleanroom garments constructed of nonwoven materials were used in cleanroom environments because of the small pore size and availability of product from suppliers of other disposable cleanroom products.
Over the past ten years, a new generation of fabrics constructed of 100% polyester and durable carbon threads, and cleanroom compatible snaps, zippers, and binding has been developed. These garment systems are lightweight, non-linting, economical and have small pore sizes to control both non-viable and viable particle contamination. There now are fabrics specifically designed to meet the requirements of the pharmaceutical, biopharmaceutical, and medical device industries.
The validation of reusable garments versus disposable garments begins with the Master Plan. The Master Plan is the overview of the life cycle of the validation process. A Master Plan outline is created that defines the steps and benchmarks of developing the validation protocol, the installation qualification, operation qualification, performance qualification, and change control.
In all of these phases, Standard Operating Procedures (SOPs) are prepared and serve as the blueprint to perform each of the qualifications. A change control process is used, if any part of these results fails to meet the required specifications, to make a change to either the specification or the system.
Once the validation protocol is developed, the SOPs written, training and responsibility assigned, the validation process is initiated.
The installation qualification (IQ) documents that the reusable garment compares at minimum equally in fabric, construction, and barrier specifications, if not better than the currently used disposable garments. All of this supporting data and documented evidence is usually provided by the supplier of the reusable and disposable garments.
The operation qualification (OQ) documents that the reusable garment system compares equally during normal processing operations, if not better than the currently used disposable garments. Typical environmental monitoring test results of both viable and non-viable particles of the cleanroom air, surfaces, and personnel monitoring should provide the required documented evidence to compare the reusable garment system versus the disposable garment system.
The performance qualification documents that the reusable garment system compares equally over an extended period of time, if not better than the currently used disposable garments. The same environmental monitoring test results of both viable and non-viable particles of the cleanroom air, surfaces, and personnel monitoring should provide the required documented evidence to prove the reusable garments are as robust and reproducible as the disposable garments.
During the validation process, changes may be required. Change control is the process to provide documented evidence of any change that has been performed, for any reason. Once it is determined that change is required, the change is documented and implemented. After implementation of the change, the changed process must be revalidated.
Once all the documentation is accumulated from the installation qualification, operation qualification, and performance qualification, a summary report is prepared. This completes the validation process and completes the execution of the Master Plan. The summary consists of a summation of the life cycle that has been outlined in the validation protocol, documentation of the testing, and verification of test data. Once data is compiled and verified, statistical analysis is performed on the data and included in the summary report.
The reusable garment systems are more economical and durable than the disposable garment systems. How many times have you put your foot through the leg of a disposable system and torn the disposable material?
Additionally, the reusable systems are more environmentally friendly. With the introduction of the ISO Environmental Standard 14000, the use and cost of disposal of all disposable products is scrutinized by upper management and the government.
For more information, please contact Jan at eudyj@cintas.com. If you have a question for Jan on cleanroom apparel, send it to pnesdore@a2c2.com.

Standardized Cleaning Approach For A New Pharmaceutical Compound

By: J-M. Cardot and E. Beyssac
June 2008


In the past, cleaning or cleaning validation problems were often pointed out by the authorities. A simple and standard cleaning approach can be used in the pharmaceutical industry in absence of specific know-how in order to initiate a reflection about cleaning.
Insufficient or inadequate cleaning can have various consequences. From a health point of view, an absence of good cleaning can lead to contaminated drugs with a risk for patients, but also for the workers within the pharmaceutical company due to a lack of correct protection. The ecological problems can be summarized in pollution risks. The regulatory issues are linked with warnings from agencies up to possible authorization withdrawn. Economic problems start with a diminution of production and stock shortage which imply increased internal costs and financial loss. In addition, image problems for a company exist when patients must return medications to the pharmacy as in the case of batch recall. Agencies can increase inspections due to a lack in confidence, and financial institutions could rate a company as a higher risk due to profit diminution and poor predictability of the potential benefits.
A clean product, surface, apparatus, fluid, or gas is one “with an acceptable and predefined level of contamination.”⁹ Contamination is defined as “the presence of contaminant” and contaminant means “a solid, liquid, biological, or gaseous matter, a microorganism, or any combination of these likely to alter in any way the health or safety of workers, patients, product or process.”⁹ Cleaning and cleaning validation are continuous processes from the beginning of development until full production and included periodic revalidations. EU GMP annex 15¹ stresses that “Facilities, systems and processes, including cleaning, should be periodically evaluated to confirm that they remain valid. Where no significant changes have been made to the validated status, a review with evidence that facilities, systems, equipment and processes meet the prescribed requirements fulfils the need for revalidation.”
One main problem is when a first batch of a new product must be manufactured, for example, for the first clinical trials. According to EC 20/2001 guidelines, clinical trial material needs to be produced under GMP conditions, and typically pilot plants are multi-product facilities. It is obvious that “Non-dedicated equipment should be cleaned according to validated cleaning procedures between production of different pharmaceutical products to prevent cross-contamination.” ¹¹ As a general concept, until the validation of the cleaning procedure has been completed, the product contact equipment should be dedicated.⁸ A highly potent or allergenic product emphasizes those problems.
The aim of this article is to bring some idea about a general concept to approach cleaning and cleaning validation for a new compound.
CONTAMINATION AND CLEANING
Contamination is a process with three main factors: the source of contamination (i.e. previous API or excipients, cleaning agents), the vector (for example, unclean apparatus or co-workers), and the receptor (for example, the next batch). Numerous solutions exist to break the links between the factors, and cleaning is one of the most critical. Cleaning should be efficient in all parts of the equipment, but also in rooms and for all the parts or places in which contamination could exist. Some zones which are not easy to clean (O rings, U-bend, etc.) are often called critical points that are defined as “zones or spots in systems on which an absence of control will bring an unacceptable risk for security.”⁹
To determine a cleaning strategy for a new chemical entity entering in phase 1 development, some information is needed first:

• Characteristics of the products: toxicities, and solubility degradation products that might appear during the cleaning, etc.
• Characteristics of the equipment: presence of cleanin- place (CIP), ease of dismantling or access without risks, compatibility of the material with the cleaning
• Characteristics of the production: use of specific apparatus, plan of utilization
• Possible cleaning processes: cleaning agents including type of solvents; mechanical actions including the type of cleaning (CIP, COP, manual); possible contact duration, possible temperature of the cleaning solvent, and time elapsed between end of production and cleaning

CHOICE OF CLEANING STRATEGY
Before any cleaning strategy is decided, a standardized approach must be set up within the company. This approach includes the use of a standard template for the cleaning procedure that must be adapted to each case as a new procedure or as specific instructions, and include a full checklist of all the points to take into consideration. The idea of a standard approach is presented in Figure 1.

As an example, a standard approach could contain at least, after a full description of the rationale and of the process, the following:

• Characteristics of the products to be cleaned: physico-chemical, toxicity, risk assessment, etc.
• Cleaning type: manual, clean out of place with dismantling instructions, or clean in place
• Type of detergent and solvent: including T°, concentration/ dilution, rinsing instructions with the choice’s rational, cleaning agent and solvent composition, and their approval as well as the presence of a method to detect their traces
• List of equipment, rooms, and utensils to be cleaned: including non-trivial ones such as co-workers clothing. For each operation of the process, a list of all the possible parts in contact with the products should be established including equipment, rooms, products (with their toxicity), surfaces in contact with possibilities of leachability (O rings, for example), type of contact (direct, indirect), flow of personal materials, products, and equipment
• Cleaning process: including time between end of production and cleaning, safety procedures for co-workers, and its critical parameters
• Rinsing process: including type and quality of solvents, for example, WFI water for equipment dedicated to sterile production
• Sampling type: rinse or swab, the placebo approach being not recommended. The sampling technique selected should be capable of detecting both insoluble and soluble residues with a good recovery. For swabbing, the choice of swab material and solvent are important: no interference, good dissolution properties, no particle release, safe for co-workers and equipment. For rins ing, the procedure must include at least: the type, volume, temperature of solvent, maximum time elapse during the cleaning and rinsing (to avoid over dried contaminant), and contact time with the solvent. For both techniques, the recovery must be calculated.
• Sampling procedure: including, when appropriate, the site of sampling and its justification, number of sample, surface, solvent type, volume, etc.
• Sample handling and identification: including time between sampling and analysis
• Analytical procedure and its validation: As stated in annex 15 of the European GMP¹ “Validated analytical methods having sensitivity to detect residues or contaminants should be used. The detection limit for each analytical method should be sufficiently sensitive to detect the established acceptable level of the residue or contaminant.” Validation of the analytical method might follow ICHQ2,⁶ for example, for rinse water and TOC. The validation reference must include the fact that TOC is validated and adapted for the traces of the compounds under consideration.
• Limits: with a rationale of the limits and the interpretation of results including non-conformity management
• List of all procedures, protocol and references: existing within the company about cleaning

DETERMINATION OF CLEANING LIMITS
For a new product limit definition is not simple. For existing and well known drug, limits are defined in the Canadian Guideline (2) or PIC/S:¹⁰
“ Carry-over of product residues should meet defined criteria for example the most stringent of the following criteria (i, ii, iii):
(i) NMT (Not More Than) 0.1% of the normal therapeutic dose of any product to appear in the maximum daily dose of the following product;
(ii) NMT 10 ppm of any product to appear in another product;
(iii) No quantity of residue to be visible on the equipment after cleaning procedures are performed. Spiking studies should determine the concentration at which most active ingredients are visible.
(iv) For certain allergenic ingredients, penicillins, cephalosporins or potent steroids and cytotoxics, the limits should be below the limit of detection by best available analytical methods. In practice this may mean that dedicated plants are used for these products.”
In the case of a new agent without any known daily dose (for example, for the first clinical batch), the first step is to consider the NOEL (no observable effect level) and calculate the first dose to be administered in humans. Based on this expectation, a 0.1% rule can be applied in a first attempt.^3,5 In the case of a formulation used both for adults and children, the worst case scenario (children) is often taken into account to calculate the limits.
Before any production on the real plan for a new chemical entity, cleaning and recovery testing should be performed, for example, on coupons of the various materials used in production over a range of concentrations (low, medium, high). A recovery of 95% can be considered as good, in the case of lower recovery, the reason of the poor recovery must first be found.
VALIDATION OF CLEANING
As in all processes, cleaning validation is mandatory and must verify the effectiveness for removal of all moieties including product residues, degradation products, preservatives, excipients, and cleaning agents. Normally only cleaning procedures for product contact surfaces of the equipment need to be validated. As presented in EU GMP annex 15¹, validation of cleaning processes should be based on a worst-case scenario including challenge of the cleaning process (usage of reduced cleaning parameters such as overloading of contaminants, over drying of equipment surfaces, minimal concentration of cleaning agents, and minimum contact time of detergents) to ensure that the cleaning process is able to work in all cases. At least three consecutive applications of the cleaning procedure should be performed and shown to be successful in order to prove that the method is validated.¹ The interest of a validation is to reduce the analytical monitoring in the routine phase.^2,7
For first trials, specifically non-toxic compounds can be used, such as colorants or riboflavin which can be visually detected at low traces. In the case of highly potent drugs (substances either toxic or hazardous), products which simulate the physicochemical properties of the substance to be removed should be considered, for validation purpose before the final test, instead of the substances themselves.¹ In the case of a series of compounds exhibiting similar characteristics (follow-up products or products of the same series), cleaning procedures for products and processes which are very similar do not need to be individually validated, this could be dependent on what is common, equipment and surface area, or an environment involving all product-contact equipment. In addition, raw materials sourced from different suppliers may have different physical properties and impurity profiles. When applicable, such differences should be considered when designing cleaning procedures, as the materials may behave differently.
Special attention must be paid to providing information to co-workers. As defined in the WHO GMP¹¹ “The manufacturer should provide training in accordance with a written programme for all personnel whose duties take them into manufacturing areas or into control laboratories (including the technical, maintenance and cleaning personnel) and for other personnel as required.”
For a new compound which exhibits allergenic properties or which is a highly potent drug, dedicated equipment and plants should be anticipated as described in the above mentioned guideline but also in ICH Q7A⁸ “The use of dedicated production areas should also be considered when material of an infectious nature or high pharmacological activity or toxicity is involved (e.g., certain steroids or cytotoxic anti-cancer agents) unless validated inactivation and/or cleaning procedures are established and maintained.”
CONCLUSION
For a new chemical entity, the main problem is often to produce the first GMP batch in facilities which are not dedicated. In the case of non-adequate cleaning or an absence of cleaning validation, the plant should be considered as dedicated until the absence of contaminant is proven. The entire problem with new chemical entities is to make a good risk assessment analysis before any operation in GMP plants.
References

1. Annex 15 to the EU Guide to Good Manufacturing Practice, July 2001
2. Canadian Health Products and Food Branch Inspectorate Guidance Document, Cleaning Validation Guidelines, June 2002
3. David C., Naumann B., Hecher L., Setting health based residue limits for contaminants in pharmaceuticals and medical devices, Quality Assurance: Good Practice, Regulation and Law, 1992, Vol I, No. 3, pp 171-180
4. FDA, Current Good Manufacturing Practices
5. Fourman G. and Mullen M., Determining cleaning validation acceptance limits for pharmaceutical manufacturing operations, Pharmaceutical Technology, (April 1993) pp. 54-60
6. ICH Q2(R1), Validation of Analytical Procedure: Text and methodology, November 2005
7. ICH Q9 Quality Risk Management, June 2006
8. ICHQ7A Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients, August 2001
9. NF EN ISO 14644 Clean Rooms
10. PIC/S Recommendations on Validation Master Plan, Installation and Operational Qualification, Non-sterile Process Validation, Cleaning Validation (PI 006-2), July 2004
11. WHO, cGMP, 2007

J-M. Cardot and E. Beyssac, Professors, Univ Clermont 1, UFR Pharmacie, ERT-CIDAM, Biopharmaceutical Department, Clermont- Ferrand, F-63001 France; e-mail: j-michel.cardot@u-clermont1.fr. Correspondence to: J-M Cardot, Biopharmaceutical Department, 28 Place H. Dunant, BP 38, 63001 Clermont-Ferrand, France.

Cleaning of Isolators and Bio-Safety Cabinets

By: Howard Siegerman and Karen Bonnell
September 2006

Good contamination control practices and adherence to established, written SOPs can minimize cross-contamination in isolators and bio-safety cabinets.
Isolators (Figures 1 and 2) and bio-safety cabinets, also known as “safety cabinets,” “biocontainment isolators,” “containment isolators,” or “barrier isolators” (Figure 3) are well accepted as cost-effective, convenient, and compact controlled environments that provide product and personnel protection. These devices consist of protective enclosures that physically isolate products from the background environment (the room outside the isolator), either because the product of interest is unsafe and therefore needs containment or the product cannot tolerate contamination and therefore needs isolation. Collectively, they are known as “separative enclosures,” or more properly, “separative devices.”
The term “isolator” is usually reserved for pharmaceutical and pharmacy applications, whereas the term “bio-safety cabinet” (BSC) is used in the pharmacy, biotechnology, and microbiology industries. For this discussion, we will consider that isolators and Class II bio-safety cabinets (and associated transfer devices) in biotechnology, microbiology, pharmaceutical and pharmacy applications are used as ISO Class 5 devices in terms of air particle cleanliness and are maintained as sterile environments to a sterility assurance level (SAL) ranging from 10-3to 10-6depending upon application.
Some applications, such as the handling of cyto-toxic drugs, potent hormones, and radiopharma-ceuticals, require both containment and isolation to achieve both protection of personnel from the product and protection of the product from contamination. Brian Midcalf, Chairman of the Pharmaceutical Isolator Working Party and User Group and Assistant PTQA Course Director, University of Leeds, UK, points out that progression from product isolation to product containment to product isolation and containment represents movement along what could be considered the “separation continuum.” These activities would typically be done in a Class II bio-safety cabinet or compounding aseptic containment isolator (CACI) where the necessary levels of air particle control and sterility would be maintained.

Figure 1. Pharmaceutical
Isolator (Photo courtesy of Getinge,
La Calhene)

Figure 2. Compounding Aseptic
Isolator (Figure courtesy of NuAire, Inc.)

Figure 3. Bio-safety Cabinet
(Photo courtesy of The Baker Company)

In applications where containment only is required, air flow is directed into the enclosure from the outside environment and filtered air is exhausted. This arrangement would suffice for a Class I bio-safety cabinet. Conversely, where product protection is need, filtered air is delivered to isolators that maintain a net positive pressure to the background environment. This arrangement would suffice for a pharmaceutical isolator or a compounding aseptic isolator in which containment is not required because hazardous products are not involved. Where containment and production protection are required, air flow into and out of the separative enclosure is filtered, using BSCs and CACIs.
In order to maintain product quality and integrity, it is necessary to clean isolators and bio-safety cabinets on a regular basis with appropriate cleaning products according to established and validated standard operating procedures (SOPs). Some isolators can be cleaned with clean-in-place (CIP) systems using spray wands. Others require manual cleaning with wipers, mops, cleaning agents, and if necessary, disinfectants. For the latter category, this article addresses the wipers and mopping systems that are best used for isolators and bio-safety cabinets and provides recommendations on optimum cleaning techniques. The manner in which pharmaceutical isolators, compounding aseptic isolators (CAIs), and bio-safety cabinets are used is sufficiently different that different cleaning (and disinfection) approaches are needed. Suggested protocols and recommended products are provided for the three applications. The reader may also wish to refer to publications dealing with the cleaning of aseptic pharmaceutical environments for additional background information.^1-6
Optimum Cleaning Procedures
Cleaning of separative enclosures such as isolators and bio-safety cabinets requires specialized procedures for optimum results — procedures termed as “critical cleaning.” These procedures are counterintuitive and differ from the casual, cursory wiping approach that is used to clean a kitchen counter at home. While old and worn cotton dishtowels (often not replaced for many days) may be used in a circular motion to clean up spills or soils on kitchen countertops, this approach cannot be employed for separative enclosures. Neither the wiping material nor the wiping action would be appropriate for isolators and safety cabinets. The kitchen counter may look clean — in fact, it may appear clean enough to eat on (this probably speaks more to the tolerance of the human body for environmental bacteria than the apparent cleanliness of the counter) — but it is still not clean enough for the contamination requirements of a separative enclosure. Fortunately, several sources^7-8 provide guidance for best practices for critical cleaning.
One could well ask, “Why bother with wiping? Why not just spray with alcohol to clean the surface?” The case for wiping as opposed to merely spraying was effectively made by Cockcroft and co-workers ⁹ who studied disinfection techniques for transfer of components into hospital pharmacy cleanrooms. They stated “…spraying [with alcohol] may reduce the bioburden slightly, but wiping is much more efficient and a combination of spraying and wiping gave the best results.” Further, the following points were made: “If a disinfectant wipe is used, two modes of action come into play. Particles and microorganisms are removed from the surface on to the wipe as the fibers pass over the surface, or the microorganism is killed by the disinfectant. If not killed by the disinfectant, the micro-organisms collected will remain on the wipe unless transferred by contact with another surface such as the hand manipulating the wipe. For this reason, it is recommended that a fresh part of a sterile wipe is used for each wiping action and overlapping strokes are used.”
The wiping action puts the fabric in intimate contact with the surface, allowing the application of strong forces for the removal of contaminants such as bioburden. Wiping has a long and successful history for removal of contaminants from cleanroom surfaces. However, to be successful, the wiper must be used properly. Table 1 addresses the primary concerns in the use of wipers and mops for critical cleaning and provides corresponding best practices with explanations. This information is also summarized in Figure 4.

Concern	Best Practice	Comment
Effective removal of surface soils	Select wiping material that entraps soils. Fold wiper in quarters Use appropriate detergent or other cleaning agent.	Soils are collected in the fabric and discarded with the wiper Ensures full contact of wiper to surface Cleaning agent must be compatible with materials of construction used in isolators or safety cabinets
Re-contamination of surfaces already cleaned	Select non-linting fabrics Wipe in linear, overlapping strokes from clean area to dirty area. Refold wiper to expose fresh wiper surface after each stroke.	Prevents contamination of wiped surface from particles and fibers from wiper fabric Wipe vertical surfaces from top to bottom. Circular wiping action re-contaminates area just cleaned. Prevents re-deposition of contaminants picked up on previous stroke.
Deposition of residues from cleaning and disinfecting agents	Remove residues with wipers wetted with deionized water or 70% isopropyl alcohol (IPA) solution	Ensures that bare surfaces are disinfected and that unsightly residues do not accumulate
Cleaning Effectiveness	Surfaces should be free from visible contaminants after cleaning	Illuminating surface with high intensity light at an oblique angle will help to identify soils not removed. Examine the last wiper in contact with the surface to verify absence of visual contaminants on the wiper.

Table 1. Critical Cleaning with Wipers and Mops

WIPING GUIDE Follow relevant site protocol (procedures for safety,contamination,etc.) and wear cleanroom gloves. Fold wiper in mid-air into quarter folds. (Fig 1A-1C) This will produce several clean surface areas and allow better contact with the surface to be wiped. When wiping,hold the wiper so that the single-fold edge is outward toward the area to be wiped.Hold the selvages closer to your hand.(Fig 2) Use either a pre-wetted wiper or a dry wiper moistened with an appropriate cleaning agent. Wipe in one direction, overlapping wiped area by 10% to 25%.Wipe sys-tematically,for example,from top to bottom,far to near.(Fig 2) Wipe from cleanest to least clean regions of the surface being wiped. Keep track of which surfaces have been cleaned and which wiper areas are unused. Use the cleanest surfaces of the wiper. If re-wiping use clean wiper area,not used wiper area. Dispose of wipers according to site procedures.

Wiping Wet Spills Identify the spilled liquid.Follow the Material Safety Data Sheet (MSDS). Choose wiper and gloves that will not be degraded by liquid. For hazardous spills,wear two pairs of gloves and try to keep the gloves dry.Wear any other necessary protective gear. Use dry wipers to wipe spills up im-mediately,then wipe slowly. Dispose of wipers according to site procedures.

Figure 4. Wiping Guide

Cleaning and Disinfection of Pharmaceutical Isolators
Overview
This section deals with the cleaning and disinfection of pharmaceutical isolators used to conduct aseptic filling operations, sterility testing, cell culturing, and purification activities, among others. Later in this article we deal with the cleaning and disinfection of compounding aseptic isolators used by pharmacies. Both types of isolators are rated as ISO Class 5 devices in terms of air particle cleanliness and are maintained as sterile environments to an SAL ranging from 10 -3 to 10-6.
Akers and Agalloco¹⁰ have pointed out that there are no substantial differences between an isolator and a cleanroom as far as the cleaning of product contact surfaces are concerned. Obviously, an isolator is smaller in volume than a cleanroom, with a correspondingly smaller footprint. But both need to be cleaned and disinfected and these processes should be thorough, consistent, convenient, and validatable. Previous publications have addressed the general topic of cleaning of isolators.^11-16 This section, however, focuses on details such as wiper selection, wiping procedures, protocols and step-by-step guidelines for isolator cleaning. Commercial training programs for isolator cleaning and use are also available.^17-18
Wipers and Mops for Cleaning and Disinfection of Isolators
Much of the literature on isolator cleaning refers to the need for “low-linting” fabrics that do not shed. However, little guidance is provided as to which fabric types are best. The lint that is shed from wiping or mopping materials is made up of loose fibers that are not bound to the fabric surface or that are broken free during the cleaning process. Cleaning and disinfecting solutions can promote this linting or shedding activity if inappropriate fabrics are used.
A wide variety of fabrics can be fashioned into wipers or mops for use in cleaning isolators. These include natural materials such as cotton, rayon, and cellulosics, synthetic materials such as polyester, nylon, polypropylene or foams, or blends such as polyester-cellulose combinations. Of these choices, only polyester knit fabrics have the requisite cleanliness, low particle and fiber counts, low endotoxin levels, low extractable residues, durability, and chemical compatibility that are needed for the cleaning and disinfection of isolators. Further, polyester knit fabrics can be sterilized by autoclaving or by gamma irradiation to an SAL of 10-6without loss of structural stability. The characteristically low levels of releasable particles and fibers associated with polyester knit fabrics are especially important in aseptic applications since it is well known that particles are potential carriers of bacteria.¹¹
Put simply, polyester knit fabrics used for wipers and mop covers will not contaminate isolator surfaces when used in cleaning and disinfection operations. Consequently, they represent the best choice for “non-linting” or “non-shedding” materials. The same cannot be said for other fabrics.
Sterile polyester knit wipers are used during production to clean up spills, wipe down gloves (when wetted with sterile 70% IPA), or to provide clean work surfaces. These wipers can be wetted with (i) detergents to clean the isolator, (ii) deionized water or 70% IPA [all IPA solutions described in this article are assumed to be 70% IPA/30% water (v/v), where the “water” is either water for injection (WFI) or deionized water (DIW)] to remove cleaning agent residues, (iii) disinfecting agents to disinfect the isolator, and (iv) deionized water or 70% IPA to remove disinfectant residues. Pre-wetted sterile wipers, containing 70% IPA are also available for these activities. Before IPA solutions are used for cleaning, rinsing, or sanitizing isolator surfaces, ensure that the materials of construction in the isolator will withstand repeated exposure to IPA. Some transparent materials, for example poly-carbonates, may cloud over or crack when exposed to IPA.
Cleaning and Disinfecting Frequency
Good contamination control practice would suggest that isolators and associated transfer devices be cleaned and disinfected after a production campaign, (a session in which multiple products of the same type are manufactured) has been concluded (referred to here as “post cleaning” which includes disinfection) and again before a new production campaign is begun (referred to here as “pre-cleaning” which also includes disinfection). This will avoid cross contamination. If the isolator has not been opened after “post cleaning” and if a new manufacturing campaign starts within short time (say one hour) after “post cleaning,” then an additional “pre-cleaning” step may be unnecessary. In that case, a surface sanitiza-tion of the isolator interior with sterile wipers and/or mops wetted with sterile 70% IPA may be sufficient to ready the isolator for production. Decisions on cleaning/disinfecting frequency and procedures are the province of the Quality Supervisor.
Cleaning and Disinfecting Specifics
Since the isolator is most often cleaned and disinfected while closed, to maintain the sterility of the isolator, sterile cleaning and disinfecting consumables — wipers, pre-wetted wipers, mops, cleaning/disinfecting agents, water, 70% IPA, etc. — must be introduced through an appropriate transfer device. Even if a facility’s SOP calls for the isolator to be opened for cleaning and disinfection, the use of sterile wipers and pre-wetted wipers is recommended, since they can be introduced into the isolator for in situ cleaning needs. This also eliminates the confusion of having both sterile and non-sterile wipers on hand and eliminates the need to sterilize wipers prior to use within the isolator.
The usual sequence for cleaning and disinfection includes a cleaning step, a rinsing step, a disinfecting step, another rinsing step, and if needed, a gaseous sterilization step, and a cleaning validation step. As a side note, wipers can be used to wipe down any hard surface articles that are introduced into the transfer device for use within the isolator. This will remove surface contaminants that might otherwise compromise disinfection or sporicidal treatments.
Cleaning
To ensure that each production run will be conducted in a pristine environment, it is necessary to clean the isolator to remove any residues and soils produced from the prior run. These contaminants, if not removed, would otherwise unnecessarily consume disinfectant and mitigate its application.¹⁹
Typically, small flat surface mops known as isolator cleaning tools (Figure 5), wipers, swabs, and detergents are most commonly employed for these cleaning applications. Detergent selection is based on the type of soil to be removed. Also, cleaning mechanism factors such as wetting, dissolution, oxidation, hydrolysis, enzyme action, emulsification, deflocculation, sequestration, saponification, and rin-seability can all be important in determining which detergent to use.^20-21 The detergent is applied to the surface in the manner described in Optimum Cleaning Procedures, using quarter-folded wipers with linear overlapping strokes, wiping from clean areas to dirty, and renewing the wiper surface after each stroke. Wipers are used for all surfaces within arm’s reach. Isolator cleaning tools are used for surfaces beyond arm’s reach.
Detergents also have the benefit of reducing the bioburden level on the surface; this lessens the task somewhat for the subsequent disinfection step.

Figure 5 – Isolator cleaning tool
in use (Photo courtesy of Getinge, La
Calhene)

Rinsing Following Cleaning
After cleaning, detergent residues are removed from the surfaces with wipers or mops that have been wetted with sterile deionized water or sterile 70% IPA. This will ensure that disinfectants have the opportunity to contact bare surfaces. Surfaces are considered clean when devoid of visible surface contaminants. Verify visually that the last wiper used to wipe down the surface is also devoid of visible residues.
Disinfection
The same procedures are followed for disinfection, except that liquid disinfecting agents are substituted for detergents. Disinfecting agents can include phenolics and quaternary ammonium compounds (use pheno-lics or quats, never both together). Aqueous mixtures of IPA will provide some measure of disinfection, but they are ineffective against spores. Occasionally, liquid sterilants such as sodium hypochlorite (bleach), per-acetic acid, and hydrogen peroxide will be substituted for disinfectants when sporicidal activity is needed. These sterilants can be corrosive to surfaces and are therefore used intermittently.
Rinsing Following Disinfection
The same procedure is followed here as in rinsing following cleaning. Disinfecting agent residues are wiped from the surface with wipers or isolator cleaning tools that have been wetted with sterile deionized water or sterile 70% IPA. This will eliminate the buildup of residue deposits that become difficult to remove in subsequent cleaning operations, and that will cause staining of work surfaces.
Gaseous Sterilization ²²
Once the cleaning and disinfection steps are completed, if required, the isolator can be sterilized, with a suitable sterilant such as Vaporized Hydrogen Peroxide (VHP).
Cleaning Validation
Surface sampling with swabs to verify the absence of cleaning and disinfecting agents may be required after rinsing. More details can be found in other documents.2, ^23-25 This constitutes the “post clean” described in the cleaning frequency section above. An identical series of steps would be followed for a “pre clean” operation, except that if surfaces have not been contaminated since the “post clean,” only disinfection, rinsing, and perhaps gaseous sterilization may be needed. Again, the Quality Supervisor determines what cleaning and disinfecting steps are required for any given circumstance.
Recommended Products
Table 2 lists the various cleaning tasks and the products recommended for both pharmaceutical isolators and compounding isolators, since so many of the tasks are common to both.

Cleaning Task	Recommended Products
Post-clean or pre-clean of interior walls, ceiling and deck of closed isolators	Choose one or more of the following: Isolator cleaning tool with polyester knit mop covers to reach all interior surfaces of the isolator. Sterilize the cleaning tool and mop covers before introducing them into the isolator. Dampen the mop covers with sterile WFI, sterile DIW, sterile IPA, [again IPA refers to 70% IPA, 30% DIW (v/v)], detergent cleaning solution, disinfectant solution, or liquid steri-lant as described in cleaning and disinfecting specifics. Sterile IPA-prewetted polyester knit wipers. Sterile dry polyester knit wipers. Dampen the wipers with the solutions described in 1 above, as appropriate for the cleaning task at hand. Swabs with polyester knit heads for cleaning hard-to-reach spaces, crevices, nooks, crannies, and isolator corners. These swabs can be dampened with one of the solutions described in 1 above.
Wiping down deck between compound sterile preparations	Sterile IPA-prewetted polyester knit wipers.
Cleaning up spills while isolator is in use	Sterile dry polyester knit wipers for absorbing spilled liquid, then Sterile IPA-prewetted polyester knit wipers for removing surface contamination.
Wiping down gloves while isolator is in use	Sterile IPA-prewetted polyester knit wipers.
Wiping mating and sealing surfaces between transfer isolator(s) and main isolator	Sterile IPA-prewetted polyester knit wipers.
Wiping down articles before placing them in the transfer isolator	Sterile IPA-prewetted polyester knit wipers.
Validation of isolator cleaning	Total Organic Carbon (TOC) Cleaning Validation kit.
Cleaning Background Environments	Flat surface mop with polyester knit mop covers, wetted with detergent cleaning agents, disinfectants and deionized water as described in Cleaning and Disinfection of Compounding Aseptic Isolators

Table 2. Cleaning Tasks for Pharmaceutical Isolators and Compounding Aseptic Isolators Text in black refers to tasks for both pharmaceutical isolators and compounding aseptic isolators. Text in blue refers to tasks unique to pharmaceutical isolators. Text in red refers to tasks unique to compounding aseptic isolators.

Cleaning and Disinfection of Compounding Aseptic Isolators (CAIs)
Overview
This section deals with the cleaning of isolators used in hospital pharmacies and other dispensing facilities to formulate (i.e. “compound”) individual prescriptions for patient care. As for pharmaceutical isolators, CAIs are rated as ISO Class 5 devices in terms of air particle cleanliness and are maintained as sterile environments to an SAL of 10-3. In the United States, the cleaning and disinfecting of CAIs and the associated background environments fall within the province of the U.S. Pharma-copeia’s document USP <797>.¹² CAIs are not used in exactly the same manner as the isolators used for pharmaceutical manufacturing. There are few opportunities to run extensive production campaigns with CAIs. A licensed compounding facility producing cancer treatment drugs, for example, may produce batches of identical products numbering in the tens or low hundreds, but a typical hospital pharmacy is more likely to have a “manufacturing run” of just a single preparation (or perhaps a few doses of the same drug), transferred aseptically into a vial, intravenous (IV) bag, syringe, infusion device, etc. These are termed compound sterile preparations (CSPs) in the industry. While the extensive cleaning and disinfection procedures previously described for pharmaceutical isolators are unnecessary and obviously impractical here, some form of cleaning and surface saniti-zation of compounding isolators will be required to prevent cross-contamination.
The cleaning and disinfection activities for CAIs will be separated into three areas:

• Cleaning and disinfecting the CAI at the beginning of each shift
• Cleaning and sanitizing the interior of the CAI between CSPs
• Cleaning the background environment.

At the outset, and to state the obvious, it must be emphasized that any cleaning, sanitizing, disinfection, or sterilization procedures must never be done while compounding activities are underway.
Many of the guidelines for cleaning and disinfection of pharmaceutical isolators, apply here as well. To save space, only specifics that are unique to CAIs will be covered below.
Selection of Wipers and Mop Covers
From a best practice viewpoint, knit polyester wipers and mop covers are again preferred for their low particle and fiber release characteristics for use in these ISO Class 5 isolators. It is recognized that some facilities will consider that blended fabrics of polyester-cellulose (discussed later) may suffice for CAIs. If such fabrics are used within the isolator, the pharmacist should recognize that they do carry a risk of higher particle and fiber release onto the isolator surfaces.
Cleaning and Disinfecting the CAI at the Beginning of Each Shift
The procedures here are identical to what is done for pharmaceutical isolators.
Cleaning and Sanitizing the Interior of the CAI between CSPs
To avoid cross-contamination between CSPs, the accepted procedure is to wipe the counter or “deck” of the isolator with a wiper wetted with 70% IPA. Pre-wetted wipers are most convenient for this task. This will remove any residues from the work surface and will provide a measure of surface sanitization as well. IPA is a versatile cleaning agent and will remove many different types of soils. Some residues may only be water soluble, so in those cases, wipers wetted with water for injection (WFI) should be used to remove the surface soils. A final wipedown with IPA will leave the surface clean for the next CSP. A second IPA-wetted wiper should be used to wipe down the gloves to guard against cross-contamination in the preparation of the next CSP.
If the CAI is used for compounding hazardous drugs, then swab sampling of the interior surfaces with subsequent analysis may be appropriate to prove that the compound of interest is not present at levels which would constitute an exposure limit danger.
Cleaning and Disinfection of Background Environments
The USP <797> document requires that floors in the background environment (also termed “buffer or clean area”) be mopped daily, while walls, ceilings, and shelving are to be mopped monthly. To accomplish these tasks most effectively, the following procedure, utilizing a single flat mop with replacement mop covers can be employed.
1. Place a clean dry mop cover on the mop head and wet it with a suitable liquid cleaning agent – either detergent or 70% IPA – to clean the ceilings, walls, and floors of the background environment. Use linear, overlapping strokes to ensure all surfaces are cleaned thoroughly (Figure 6). If the mop cover becomes visibly dirty during the cleaning process, replace it.
2. If 70% IPA was used in step 1 proceed directly to step 3. If a detergent was used, place a clean mop cover on the mop head, then dampen it with either deionized water or 70% IPA. Use linear, overlapping strokes to remove the dried cleaning agent residue. Again, if the mop cover becomes visibly dirty during the cleaning process, replace it.
3. Place a clean mop cover on the mop head and spray the mop cover with an approved disinfectant (e.g., phenolic or quaternary ammonium compound) solution. Spread the disinfectant over the ceiling, walls, and floors with linear, overlapping strokes. Alternatively, spray the ceilings, walls, and floors with the disinfectant and spread the disinfectant solution evenly over the surfaces with the mop. Allow appropriate kill time (e.g., 10 – 20 minutes) for the disinfectant to do its job.
4. Place a clean mop cover on the mop head, then dampen it with either deionized water or 70% IPA.
Use linear, overlapping strokes to remove the dried disinfecting agent residue. Again, if the mop cover becomes visibly dirty during the cleaning process, replace it.
This procedure will ensure that the background environment outside the compounding isolator will meet the requirements for USP <797>.

Figure 6 – Flat surface mop for
ceiling, wall, and floor cleaning

Recommended Products
Refer to Table 2 for the various cleaning tasks and the associated products recommended for CAIs. Ignore the blue text in Table 2 which refers to tasks unique to pharmaceutical isolators. Tasks relevant to CAIs are in black and red.
Cleaning Bio-safety Cabinets
Overview
As stated previously, bio-safety cabinets are used to protect operators from the hazardous materials within the cabinet. Class II bio-safety cabinets (used for handling cytotoxic drugs, potent hormones, active pharmaceutical ingredients, etc.) and CACIs that are maintained sterile with ISO Class 5 air particle levels, would be cleaned according to the guidelines laid out previously for pharmaceutical isolators or compounding aseptic isolators. These cabinets require the use of polyester knit fabrics to maintain the necessary particle levels within the separative enclosure.
However, some bio-safety cabinets, such as the Class I category, do not require that the interior of the separative enclosure be kept sterile, do not require that ISO Class 5 air quality be maintained and typically do not incorporate glove ports. For these applications, fabric selection for wipers and mop covers can be relaxed somewhat.
Selection of Wipers and Mop Covers
The blended polyester-cellulose materials that were previously considered too contaminating for pharmaceutical and compounding isolators will be quite suitable for most Class I bio-safety cabinet applications.
Cleaning Specifics for Class I Bio-safety Cabinets
The cleaning specifics for Class I bio-safety cabinets are similar to those for pharmaceutical isolators, except that cleaning activity can be confined to the end of a manufacturing campaign and sterile consumables need not be used. Again, the desire is to prevent cross-contamination from one manufactured product to another. However, since there is no need to maintain sterility, one can reasonably assume that if the bio-safety cabinet interior is cleaned thoroughly and is validated, there should be no need to clean again prior to the beginning of the next manufacturing campaign. These are broad guidelines however, and the protocols defined by the Quality Supervisor must be observed.
One further cleaning activity bears mention. Since the production activity involves hazardous materials, it may be prudent to wipe down the exterior of the manufactured product to ensure that dangerous substances are removed prior to the product being transferred out of the bio-safety cabinet. These wipers, and those used to clean the interior of the bio-safety cabinet, must be appropriately bagged and transferred out of the separative enclosure in a safe manner.
The wipedown procedures follow the same procedures as described in the “Optimum Cleaning Procedures” section. Using linear wiping patterns from clean to dirty (usually top to bottom, front to back), with overlapping strokes, quarter-folding the wiper after each stroke. Since hazardous materials are being removed from surfaces, consideration should be given to changing the wipers frequently. After cleaning, suitable validation tests should be run to verify the absence of the hazardous material involved. Obviously, the bio-safety cabinet must be thoroughly wiped down and decontamination procedure verified before the enclosure is opened to the background environment.
Recommended Products
Table 3 lists the various cleaning tasks and the products recommended for BSCs.

Cleaning Task	Recommended Products
Cleaning of interior walls, ceiling, and deck of closed BSCs at the beginning of each shift	Choose one or more of the following: Isolator cleaning tool with blended polyester-cellulose mop covers to reach all interior surfaces of the isolator. Dampen the mop covers with DIW, IPA, detergent cleaning solution, disinfectant solution or liquid sterilant. IPA-prewetted blended polyester-cellulose wipers. Dry blended polyester-cellulose wipers, wetted with the solutions described in 1 above, as appropriate for the cleaning task at hand. Polyurethane foam swabs for cleaning hard-to-reach spaces, crevices, nooks, crannies, and BSC corners. The swab can be dampened with one of the solutions described in 1 above.
Cleaning up spills while BSC is in use	Dry blended polyester-cellulose wipers for absorbing spilled liquid, then IPA-prewetted, blended polyester-cellulose wipers for removing surface contamination.
Wiping down gloves while BSC is in use	IPA-prewetted, blended polyester-cellulose wipers.
Wiping mating and sealing surfaces to BSC	IPA-prewetted, blended polyester-cellulose wipers.
Wiping down articles before placing them in the transfer device	IPA-prewetted, blended polyester-cellulose wipers.
Wiping down manufactured articles before transferring them out of the BSC	IPA-prewetted, blended polyester-cellulose wipers.

Table 3. Cleaning Tasks for BSCs

Summary
The manner in which pharmaceutical isolators, compounding aseptic isolators and bio-safety cabinets are used dictate the somewhat varied approach to cleaning and where applicable, disinfection practices. Good contamination control practices and dedicated adherence to established, written SOPs will minimize cross-contamination surprises.
Acknowledgements
The authors wish to thank Brian Midcalf at University of Leeds, Eric Kastango at Clinical IQ, and Scott Christensen and Bill Peters at NuAire for their review of the manuscript and for providing helpful comments. Details on isolator construction and usage were also supplied by Craig Johnson of CPS Pharma and Patrice Cloue of La Calhene.
References

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Howard Siegerman is Director of Technology for ITW Texwipe,concentrating on contamination control in the electronic and life science markets.He earned B.Sc.,M.A.,and Ph.D. degrees in analytical chemistry from the University of Toronto. Dr.Siegerman holds two patents and has authored a number of technical publications. He can be reached at 201-684-1800 x 220 or hsiegerman@texwipe.com

Karen Bonnell is a Product Manager for ITW Texwipe.She manages the mop line of cleanroom consumables,including mops, pre-wetted and dry mop covers,and isolator cleaning tools.Ms.Bonnell received an M.A.in Biochemistry from Temple University and a B.A.in Biology from Bryn Mawr College.She can be reached at 201-684-1800 x 318 or kbonnell@texwipe.com.