“Perfect” Cleaning Process? New Guidance

High-value product has to be clean to function reliably; but nearly all manufacturing processes inevitably generate soils. You should know about an important new guidance document. While it is designed for medical device manufacturing, it should be of value to anyone concerned with cleaning and contamination control.

“Tell me the perfect cleaning process for medical device manufacturing so that nothing will go wrong.” We hear that request from the manufacturing and regulatory communities. Our response? “Sure thing! We’ll get right on that after we give you the formula for eternal youth.” A single cleaning process for the entire medical device community would be wonderful. However, given the variety of shapes, materials of construction, and usage requirements, a universally-applicable, fool-proof cleaning process is not possible. For near-term solutions, we suggest you consider a consensus document that we were involved in developing: ASTM F3127-16 “Standard Guide for Validating Cleaning Processes Used During the Manufacture of Medical Devices.”(1) Even if you don’t manufacture medical devices if you are concerned with cleanliness, contamination control, and reliability for high value product, consider perusing the guide. We think it provides sensible, practical guidance for manufacturers. Here are a few highlights.

Validation Readiness: supply chain and final assembly
Cleaning validation ought to be simple. It’s the “validation readiness” that is the real challenge for device manufacturers. ASTM F3127-16 can be used for validation readiness. It is useful for manufacturers who are developing newer devices, devices which are not necessarily closely analogous to those currently in use.  Because each manufacturer would use the guide relative to the particular device in question, it is not a step-by-step list of “thou shalts.”

The terminal cleaning may not be the critical cleaning step. We sometimes hear comments from contract manufacturers indicating that cleaning is not necessary, because the final device assembler will take care of cleaning activities. The guide provides an approach to validating removal of contaminants and residue  (including cleaning agent residue) at interim process steps. Therefore, it will be useful for evaluating, validating, and monitoring cleaning throughout the supply chain. There is a clear signal that the cleaning activities of job shops and specialized contract manufacturers must be effective, clearly defined, and well documented.

Other points of interest
This is a comprehensive document. Here are a few additional points of interest. The definition of soil (referred to as the contaminant in the standard) is noteworthy in that it encompasses a material or mixture with the potential to adversely impact the assembly process, the functioning of the device, and/or interaction with the host.  The guide also calls for understanding and defining cleaning processes, including excluding processes like passivation that some may consider to be cleaning but that most often are not a substitute cleaning. 

Validation is not like the Olympics; a gold metal doesn’t just sit on the shelf; manufacturers have to keep going for the gold. That is, validation of a cleaning process isn’t (or shouldn’t be) a one-time event – we need ongoing vigilance. In support of ongoing validation, the guide covers process monitoring, including tracking of trends.  One section covers analytical techniques and sampling techniques. Rather than simply providing a laundry list of the “sexiest” high-tech analytical techniques, the emphasis is on understanding whether or not the technique is providing the appropriate information with the correct level of sensitivity and specificity.  The appendix includes validation examples and even some common questions to answer to achieve “validation readiness.”

Noting that cleaning is essential for biocompatibility and reliable function, the guide encompasses cleaning of devices during initial manufacturing and before initial use. In any standard or guide, exclusions are perhaps as important as the scope. The edges of many standards can be a bit “fuzzy,” especially in areas of cleaning and surface quality.  In this case, exclusions are clearly stated. The guide does not cover cleaning of devices in health care facilities.  Excluding cleaning in health care facilities is significant. In health care the soils encountered are generally not the same as those used in initial manufacturing. In addition, there is the challenge of achieving reliable cleaning while assuring correct, timely patient care. While the guide does not cover manufacture reusable devices, there is a notation that many principles outlined can be applied to validation for reusable devices.

The guide is encompassing. It is not restricted as to the type of medical device or as to the materials of construction. It covers an array of current and perhaps near-future devices. ASTM guide may prove complimentary to the recently released FDA draft guidance for 3D printed devices (2).

Cleaning and validation issues cross-over among fields. In our own consulting practice, we find that we are able to draw on approaches from one area of critical cleaning and, with appropriate adaptation, adapt those approaches to solve other cleaning problems. For example, in 3D printing, aerospace has had significant presence in FDA programs. The ASTM guide draws on cleaning validation approaches for other high-value product such as semiconductors, electronics, and for product used in oxygen-rich environments. It also provides examples from diverse fields. Please, don’t be hesitant to reach out to other fields for validation approaches. Notice we said “adapt,” not adopt; we said “draw on,” not accept without question. This guide requires you to use your brain. By doing so, you can achieve reliable, defendable processes.

1. ASTM Standard:

2. FDA Guidance : http://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM499809.pdf

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