Q&A with Kate Douglass, MS, RN, QP503A qualified,
and Abby Roth, CMQ/QE, QP503A qualified
Despite the fact that USP <797> was published in 2008 and 2019 (the 2019 version has been returned to the Expert Committee for reevaluation), many pharmacists continue to pose questions about the intricacies of compliance with the Chapter. In this article, which is Part 2 of a 3-Part series, the authors identify and discuss specific cleaning questions related to USP <797> compliance. While the questions and answers are based on USP chapter requirements, the focus is on best practices.
Part 1 of this article is available at pppmag.com/article/CleaningPart1
Pharmacy Purchasing & Products: What is the process for cleaning primary engineering controls?
Kate Douglass and Abby Roth: Following the principles already outlined in Part 1 of this 3-part article, we recommend general nonhazardous primary engineering control (PEC) cleaning in this order (see PHOTO 1):
Another option is to clean the sides first and then the back; either order is acceptable, provided all staff members clean the PEC identically and can articulate to other staff and inspectors as to why the SOP requires that specific order. Note that when cleaning the sides of the PEC, the cups on which the bar sits, the bar, and the hooks must all be cleaned manually.
We strongly encourage the use of cleaning tools, sometimes called isolator cleaning tools. It is wise to purchase a stainless steel cleaning tool for each PEC. The cleaning tools should hang inside the PEC far to the side. This tool should be left in place during smoke testing as well. If you do not place a tool inside each PEC, then workers must clean and disinfect it each time they remove it and put it inside another PEC. Of course, tools must be cleaned and disinfected before and after using, but having one in each PEC is prudent as it reduces workload.
When cleaning and disinfecting the inside of PECs, such as laminar air flow workbenches (LAFWs), workers must take care not to break the plane of the PEC by allowing their hand with the wipe or the cleaning tool to come outside the ISO 5 space. PHOTO 2 shows two methods of wiping the sides of the PECs. Though the horizontal process is most closely aligned with wiping from the cleanest to the dirtiest, this method also increases the risk that the worker’s hands break the plane of the PEC and travel outside the ISO 5 space. To reduce this risk, we recommend using the vertical approach; only in the last stroke does the worker need to be mindful not to break the plane.
PP&P: Which surfaces should be cleaned during the daily cleaning and monthly cleaning?
Douglass and Roth: Please refer to Table 8 in USP Chapter <797> (2019), which is more specific than USP <797> (2008) about the surfaces that require cleaning and disinfecting daily. TABLE 1 describes daily and monthly cleaning requirements and best practices.
PP&P: Is it necessary to use sterile IPA when cleaning the cleanroom, or is using sterile IPA considered disinfection?
Douglass and Roth: Cleaning and disinfecting have two different goals. Cleaning removes dirt and debris and readies a surface for disinfection, while disinfecting a surface destroys all microbes except their spores. Only EPA-registered, one-step disinfectant cleaners can accomplish both steps in one application. Although isopropyl alcohol (IPA) is considered a disinfectant, it is not used in cleanrooms to disinfect. To be a disinfectant, IPA would need to achieve a dwell time of 10 minutes, which is not possible in the compounding setting. Moreover, IPA is not considered a cleaning agent because it does not have a surfactant or detergent. Although IPA is useful, it is not the panacea that pharmacists have long been taught that it is.
The only place where sterile IPA must be used in cleaning activities is on the internal surfaces of the PEC. After cleaning and disinfecting with an EPA-registered, one-step disinfectant cleaner (achieving the manufacturer’s dwell time for that agent), the interior surfaces of the PEC are wiped with sterile IPA to remove residues and to further sanitize. Sterile IPA is not required elsewhere in cleaning; however, it may be used after the EPA-registered, one-step disinfectant cleaner to remove residues on windows.
We strongly recommend use of sterile IPA on the individual staging carts used by the operators during compounding. Staff should treat the staging carts identically to the PEC deck. Because staging carts are used to stage components going into the PEC, these carts are high-risk surfaces. Regular sanitization of the staging carts (and other work surfaces) with sterile IPA during the compounding day is encouraged.
Sterile IPA should not be used on ceilings, walls, floors, or other furniture. There is no rationale for its use on those surfaces, and it would certainly be cost-prohibitive.
PP&P: Is sterile water required during daily and/or monthly cleaning of the PEC?
Douglass and Roth: It is not required to use sterile water for daily or monthly PEC cleaning. The 2019 version of <797> does mention the use of sterile water to remove visible particles or other residues on the deck, but those particles or residue are most likely water-soluble and can be removed with the chosen EPA-registered, one-step disinfectant cleaner.
However, if the cleaning agent used in the PEC is not ready-to-use (RTU) and requires dilution, then sterile water should be used to prepare that agent, as tap water can contain up to 500 colony forming units (CFU) of microbes per milliliter. For an agent used in the PEC, over dilution with tap water could result in significant contamination of the ISO Class 5 space. For cleaning the PEC and the SEC, we strongly recommend using only RTU agents to avoid over-dilution and additional documentation. After surfaces are cleaned with the EPA-registered one-step disinfectant cleaner, they do not need to be wiped with sterile water to remove residue.
PP&P: If cleaning agent literature lists several contact times, which one applies to our cleanroom?
Douglass and Roth: EPA-registered cleaning agents may list tuberculocidal, virucidal, fungicidal, and bactericidal dwell times. For pharmacy purposes, select a daily cleaning agent with a dwell time of 3 or fewer minutes based on the bactericidal dwell time. The contamination control concerns in a cleanroom suite are different than a patient room, where we would not be surprised to discover viruses, fungi, and even tuberculosis. In sterile compounding cleanroom suites, we are primarily concerned with removing bacteria; if we continually focus on contamination control, it would be unusual to find these other microbes.
PP&P: Can we use agents that our infection preventionists recommend, which have a contact time of 10 minutes?
Douglass and Roth: No, because a 10-minute contact time is not achievable inside of a PEC or a cleanroom suite. A general rule is that any agent with a dwell time greater than 3 minutes is not achievable in a cleanroom suite. Remember that the contact time is the time an agent must remain wet to achieve its intended effect, which is to kill microbes. Within PECs, air blows out or down at a velocity of 80 to 100 feet per minute, so surfaces dry quickly. Inside of secondary engineering controls (SECs), such as in ante-rooms or buffer rooms, high air exchange rates must be achieved to meet ISO requirements. For example, in a buffer room, 30 air changes per hour (ACPH) is the required minimum for an ISO 7 space; as such, all the air in the room is exchanged every 2 minutes. Many buffer rooms have rates as high as 60 or even as many as 90 ACPH (ie, a full air exchange every 45 to 60 seconds).
It is important that surfaces be thoroughly wetted; one of the most frequent mistakes in cleaning is under-wetting the surfaces which also contributes to a more rapid cleaning agent dry time. If the agent’s required dwell time is not achieved, the mechanical cleaning benefit is realized but the chemical benefit is not. It is also important to note that cleaning agents have detergents or surfactants added to them to assist the agent in producing better wetting so that it spreads on the surface being cleaned and does not bead up.
Kate Douglass, MS, RN, QP503A qualified, is the vice president and chief development officer of CriticalPoint, LLC, a health care training and development company. She is a co-author of CriticalPoint’s Interactive USP Chapter <797> and <800> Gap Analysis Tools and co-director of the USP Sterile Compounding Compliance Study. Kate has personally supervised the design, engineering, and build of pharmacy compounding facilities that met or exceeded USP requirements.
Abby Roth, CMQ/QE, QP503A qualified, is director, learning and development at CriticalPoint, LLC. In her current role she develops curriculum for CriticalPoint’s e-learning modules and live training classes. She is a faculty member for the Sterile Compounding Boot Camp Live Training Series. Prior to joining CriticalPoint, Abby served as the director of microbiology for Clinical IQ, LLC, and as a quality director at a contract microbiology laboratory specializing in environmental monitoring.
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