Selecting a Medical Device Fluoropolymer Coating Applicator

Attaining exceptional product design and performance is necessary to thrive in today’s competitive business environment. There are many variables to consider regarding application requirements and selecting the appropriate solutions for medical device design and coating. There are capabilities that medical device fluoropolymer (such as Teflon®) coating applicators must have to ensure they can deliver a quality experience and product. World-class quality, quick turnaround time, and seamless integration with a proven and reliable medical device supply chain is essential, and is the price of admission to participate in the medical device industry. However, not all fluoropolymer applicators are the same.

When choosing a fluoropolymer applicator, the following six criteria should drive the selection process.

Expertise in Coating and Handling Medical Device Products

While many fluoropolymer applicators may be able to handle basic jobs, medical device projects require an applicator with deep experience and expertise to make appropriate recommendations regarding how to coat specialty items, such as guidewires, core wires, coils, needles, mandrels, and instruments. Why? Because only a supplier with this experience and expertise has the capability to reliably meet medical application requirements. The applicator will have developed systems, methods, application technology, and formulations, as well as employ extensively trained operators. This capability allows the applicator to meet the specifications and provide the coverage and uniformity, the adhesion, and a system to protect the customers’ products from damage.

Customers should expect the following from an experienced fluoropolymer applicator when evaluating their medical device coating capabilities:

• Prior experience and established FDA filings for coating similar devices.
• Recommendations on coating chemistries with various alloys.
• Tolerance adherence based on process capabilities of the coating application technology.
• Regarding nitinol wires—the supplier’s recommendation and offerings for low-cure formulations and processes.
• Regarding hypotubes—the supplier’s recommendation and offerings that do not oxidize the outer diameter (OD) or inner diameter (ID), eliminating the need for post-tarnish removal.
• Expertise with simple to complex device geometries. For example, how the supplier will handle a variety of shapes and sizes for stylets, with a range of diameter grinds throughout—with capabilities for specific fixturing and masking techniques to provide exact coating deposition throughout the length of the stylet.
• The breadth of color coating options (and batch-to-batch color consistency) to meet product and brand identification needs.

In sum, the fluoropolymer coating applicator must know the “whats” and “whys” of choosing coatings for end-use applications. It is important to understand why one device should be coated with a particular chemistry over another. Should the various types of Teflon®, polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyvinylidene difluoride (PVDF), or ethylene chlorotrifluoroethylene (ECTFE) be used? And once the coating chemistry is settled on, the applicator requires the knowledge about when to use aqueous0based or solvent-based coating formulations. When making the selection, the applicator must be able to provide biocompatible information and prior use experience to successfully manage medical device coating projects supporting regulatory approvals. It goes without saying, experience matters.

Expertise in Medical Device Cleaning Methods and Surface Preparation

Traditional fluoropolymer applicators operate in environments that are different than medical device Contract Manufacturing Organizations (CMOs) or Original Equipment Manufacturers (OEMs). Most, if not all, fluoropolymer applicators have never seen the inside of a CMO, let alone an OEM production facility. Clean rooms are non-existent and controlled air flows are adhering to basic OSHA requirements—not because of product quality, but as a result of workplace regulatory requirements. Thus, attention to surface preparation is a secondary concern.

An imperfect substrate is the primary cause of coating adhesion failure—a failure that potentially carries unacceptable patient risk. Understanding the interaction between the substrate and the coating formulation, and having the technology to control the surface before the coating is applied, is an essential capability the coater must be able to demonstrate. Given the variability of contact materials and prior conditions of the substrate before the coating application starts, the coating applicator must have surface preparation processes in house, and these process steps should be part of the overall Process Qualification when approving the vendor. (See Figure 1)

Intense Focus on Deposition Control

Coatings are controlled at the micron level and attention to deposition control is critical. Controlling deposition requires that a strict process be in place—Six Sigma protocols should guide this initiative. Adhering to a process methodology will bear consistent, reproducible outputs that meet specifications every time. Equally important is a thorough understanding of the critical process input variables (CPIVs) for deposition. As well, a coating applicator’s expertise must include the ability to understand how to manage deposition with various substrates. For example, nitinol poses different challenges than stainless steel. (See Figure 2)

Process Control Culture

Advanced medical device coating processes thrive with the right equipment that has been installed using the strictest validations, including installation qualification, operational qualification, and performance qualification (IQ/OQ/PQ) protocols. Understanding all the design specifications, then challenging them in end-stage environments produces a quality product. A responsible fluoropolymer applicator uses state-of-the-art process measurement equipment to ensure that each stage of production meets all specification requirements. This solid base is the only working model a reputable medical device fluoropolymer coating applicator should work from.

Adherence to ISO 13485

It is imperative that the fluoropolymer applicator is familiar with the same structures, guidelines, and requirements adhered to by the OEM medical device company. This starts with the applicator being fluent with the relevant FDA requirements—specifically that their systems, processes, and people are in control. This is made manifest in the supplier’s quality system being ISO 13485 certified. In addition to the quality system, it is always a good practice to conduct your own audit, as this will provide familiarity both with the supplier’s quality system, and more importantly, its company culture.

Company Culture—Medical Device Mindset

Transparency provides insurance that all parties deliver as they should. Nowhere is it more vital than in medical device markets to adhere to a full transparency policy. Fluoropolymer coating projects call for collaboration between experienced teams highly focused on strategic problem solving. Full and open communication between supplier staff is essential. When looking for fluoropolymer coating on medical devices, find a supplier that has staff with medical device experience from CMOs and OEMs—a proven track record of success from within the business provides optimal assurance for getting the best advice. What will that look like? Fluoropolymer applicator staff should be well-versed in the critical aspects of the medical device industry. They can synchronize inspection criteria, methods, and equipment, and are able to provide a clear definition of design goals. (See Figure 3)

An environment that carefully manages and controls processes and changes keeps those clearly defined goals consistently on track. Highly structured change control processes must evaluate the consequences and controls necessary to make changes, as well as gauge their impact. Design and process failure mode effects analysis (FMEAs) must be in place, any unintended consequences monitored, and change controls managed by a point person who documents changes and data, anticipates and analyzes impacts of any changes, and reports all changes to and collects approvals from all parties involved. No critical process variables change without authority—no critical process or tooling is changed, not even personnel, without being vetted, documented, and approved. All of this information should be openly available to the customer.

Maintaining optimal quality standards is at the heart of a reliable fluoropolymer coating applicator’s culture. All of the proper quality tools must be in place. Consistent and verifiable data collection through statistical process controls (SPCs) captures all upper and lower limits, which are monitored and documented so any possible process deviations are caught on the spot and addressed.

Keeping Pace with Product Design and Performance

These six items listed above are critical for a fluoropolymer coating applicator to keep pace with the increasing demands of the medical device industry— allowing customers to do so, as well. Technical demands keep intensifying, and to survive in the industry requires having a medical device mindset. In the final analysis, the fluoropolymer applicator’s culture is probably the most important of all the other five criteria. Values and culture drive behaviors, and behaviors deliver results.

This article was written by Robert A. DeAngelis, President of Precision Coating Company, Inc., Boston, MA. For more information, Click Here . MD&M East, Booth 357

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