FTIR in Assessment of Medical Devices

By: Adam B. Brigham, B.S.; Matthew R Jorgensen, PhD

Fourier transform infrared (FTIR) analysis is a popular analytical tool for material screening. The technique works because each different type of molecular bond in a molecule vibrates differently, and there is often a set of molecular vibrations that involve the entire molecule that form a characteristic “fingerprint.” When measuring a molecular substance, it is possible to identify an organic substance by comparing its FTIR spectrum to a library. In cases where a substance is a mixture of molecular components, FTIR would not be the best option because a separation technique (e.g. chromatography) would need to take place before identification could occur. However, there are many cases for which FTIR analysis is a fast and inexpensive option.

FTIR can be a useful first step as an aid in the identification of an unknown residue. Even if an exact identification is not possible (e.g. in the case of mixed residue), FTIR can often help identify the class of compound which can assist in unknown investigations or process monitoring. For example, if high residual manufacturing material was found on a device, FTIR could be used as an investigational tool to help identify the source. If FTIR was unable to find a conclusive library comparison match, additional testing would need to take place.

FTIR shines when comparing two or more materials in-hand. For example, when particulates are found on a device, it may be necessary to attempt particle identification so that the source can be found and eliminated. Other analytical chemistry techniques would fail at this task, because the amount of particulate material is too small to analyze. FTIR can be conducted through a microscope so that the “fingerprint” of a single particle can be collected. This spectrum can be compared against potential contaminants (e.g. paper, fibers from clothing, or materials unique to the device manufacture), or a library of materials which can greatly narrow the possibilities.

There are also cases where the question being asked is, “does a certain process change my material?” FTIR is a great resource for polymer characterization. Depending on the nature of the material and process, it may be possible to pinpoint what the change is. For example, oxidation of a polymer is clearly indicated by the introduction of carbon-carbon double bonds. If the details of the change are not derivable, it can at least detect if a change has occurred. Perhaps a manufacturer considers changing the radiation dose for their material; they can measure the original device and a device irradiated at the new level comparatively to see if anything is different.

Any FTIR study relevant to medical devices should be carefully thought through and designed with expertise. Simply ordering of a single test without a specific objective in mind will be marginally useful. With smart design – powerful conclusions can be made.

2017 Mid-year Thought Leadership Update

The experts at Nelson Laboratories have been busy in 2017. They have participated on committees, spoken at domestic and international industry events, written whitepapers, published articles, and hosted webinars. We have compiled the list below to share some of our educational assets:

WHITEPAPER

WEBINARS

TECH THEATER

THIRD-PARTY PUBLISHED ARTICLES

To register for our three-day Science of Sterilization Validation seminar, visit the Seminar page on our website.

WISE Committee Showcases STEM Careers

WISEThe Nelson Laboratories’ Women in STEM Education (WISE) committee recently participated in the San Juan County Sixth Annual Career Fair hosted by Junior Achievement of Utah. Tina May, Dani Silva, Jessi Beck, and Dayna Clarke are part of the WISE committee which is comprised of 17 women scientists and leaders at Nelson Laboratories who are committed to bringing the passion for STEM careers to youths of all ages.

Nelson Labs was one of over 30 vendors that visited Whitehorse and Monument Valley High Schools to teach children from grades 7-12 about career opportunities that are available for them after graduation.

“We love to participate in events like this and share our enthusiasm for science careers with students who wouldn’t normally have the opportunity to learn about these options,” said Tina May, co-chair of the WISE committee and senior director of laboratory operations at Nelson Laboratories.

There was a lot of traffic and interest at the Nelson Laboratories’ booth. The hands-on activities demonstrated to the kids that science can be cool, and they were able to take part in some of the testing protocols that are used in the laboratory. For instance, teaching the kids about aseptic technique for putting on surgical gloves was a big hit. Once they put on the gloves and held their hands under a special light, they were able to see how effectively they followed the procedure for gloving up. This also taught them why the technique is important for sterile environments.

“This experience was amazing as we got the chance to get to know many bright, young people who were genuinely excited to learn about our company and to have fun,” said Dayna Clarke, radiation study director at Nelson Laboratories. “We were also awestruck by the natural beauty of the formations of the Bluff and Monument Valley landscapes.”

Inspiring the next generation of scientists is an important mission, and the WISE committee is comprised of dedicated individuals who volunteer their time and talents to spread the word about STEM education and careers.

AAMI Sterilization Standards Meeting Update

By Jason Pope, Senior Scientist

The AAMI Sterilization Standards Week was held in Baltimore MD in March of 2017.  This set of meetings provides the opportunity for the various AAMI sterilization standards working groups to come together and provide input on numerous industry standards and guidance documents that relate to the sterilization of medical devices. One of the groups that had the opportunity to meet was ST/WG 43 – Hospital Steam Sterilizer Working Group.

During the meeting of ST/WG 43, a discussion occurred relating to the drying times recommended for healthcare steam sterilizers and the drying times listed by medical device manufacturers for device sterilization instructions. The drying times from sterilizer manufacturers are listed in the FDA Guidance Document for reprocessing of medical devices in health care settings and in AAMI TIR12.  Representatives of multiple sterilizer manufacturers were involved in the discussion and expressed a desire to change the way the documents list the drying times for steam cycles that are commonly available in healthcare settings.

Sterilizer manufacturers explained that the listed drying times was determined by sterilizer manufacturers for specific loads, devices, and test packs used in sterilizer development and validation.  The idea that the drying times, listed in the aforementioned documents, should be considered by medical device manufacturers as minimum times was discussed, with working group members indicating that medical device manufacturers may find that longer drying times are appropriate for their products during validation testing.

Several working group members expressed concern that the drying times listed in the FDA guidance document and AAMI TIR12 are being interpreted by medical device manufacturers and healthcare workers as being exact values that may not be lengthened. Discussion participants indicated that this interpretation of listed drying times is concerning if specific medical devices and loading configurations require longer drying times to ensure adequate moisture removal for device storage stability.

Nelson Laboratories has observed that the US FDA has cleared medical device submissions with drying times that exceed those listed in the FDA guidance document and AAMI TIR12. The drying time that a manufacturer includes in their device sterilization instructions should match the drying time determined by validation testing.  It is impossible for sterilizer manufacturers to perform validation testing of a steam sterilizer in a manner that encompasses all current and future device types used in a healthcare setting to care for patients. A medical device design may have characteristics that require the drying to exceed the minimum drying times outlined by sterilization manufacturers.

Due to the removal of commonly available steam sterilization cycles from the most current revision of ANSI/AAMI ST79, a desire was expressed in ST/WG 43 to add the cycle tables to ANSI/AAMI ST8 – Hospital Steam Sterilizers. Many working group members expressed the opinion that this document, written for sterilizer manufacturers, was a good home for this cycle information. Many members felt that the addition of this information to ST8 should be accompanied by verbiage clarifying that the listed drying times are to be considered minimum times, the goal being to prevent medical device manufacturers and healthcare personnel from misinterpreting the drying time information to be unalterable and to help them recognize that longer drying times may be needed for specific device types and sterilizer loads.  Additionally, clarifying verbiage will let device manufacturers and end users know that drying times should never be shortened from the minimum listed times.

The Hospital Steam Sterilizer Working Group recently decided to revise AAMI ST8 and plans to meet in the Fall of 2017.  Nelson Laboratories will have a representative in attendance at that meeting and will be providing updates after the meeting is held in Baltimore.

To learn more from our industry experts, attend one of the Nelson Laboratories’ three-day Science of Sterilization Validation seminars. Click HERE to view the upcoming seminars.

AAMI STERILIZATION STANDARDS MEETING UPDATE

By Emily Mitzel, MS

On March 20-23, 2017, I attended the Association for the Advancement of Medical Instrumentation (AAMI) semi-annual Sterilization Standards Committee Meeting. These Association meetings, and the standards discussed during them, have a major impact on medical device manufacturers, testing facilities, HCF managers, and FDA.  It is important for industry experts to participate in these meetings to ensure the standards and technical informational reports reflect current industry changes and trends, and to make sure the standards are written scientifically.

In addition to the satisfaction of positively impacting global health, participating on these committees allows me to stay up to date with the standards and understand what is trending in the industry. The clients I work with benefit because I can make sure they are meeting current and future regulatory requirements.

Highlights from the meetings include:

  • Working Group 93. TIR 30: 2011. This document needs to be updated to reflect current standards and published documents. A task committee, which included me, was established to determine the updates.
  • Working Group 40. ST79. This group finished reviewing all comments. It was noted that the document has been placed on AAMI public review but still needs to be placed on ANSI public review, and this could drive public review comments that will need to be discussed.
  • Working Group 13. ISO 15883 series. I provided an update from the February 6-8, 2017 interim meeting of ISO/TC 198/WG 13. Comments are still being resolved on ISO/DIS 15883-4, Washer-disinfectors – Part 4: Requirements and tests for washer -disinfectors employing chemical disinfection for thermolabile endoscopes, and that work will continue in April. The majority of this group’s time was spent on ISO 15883-5, Washer-disinfectors – Part 5: Performance requirements and test method criteria for demonstrating cleaning efficacy. Substantial changes and additions were made to the document during the February meetings that required discussion. ISO/CD 15883-5 is out for ballot and comment until April 2017. It was also reported that there will be a major revision to ISO 15883-1, Washer-disinfectors – Part 1: General requirements, terms and definitions and tests to begin soon.

In April, I will be attending the ISO meetings as a U.S. delegate. The standards that will be discussed at this meeting are ISO 17664, ISO 15883-1, ISO 15883-4, and ISO 15883-5.

Complete EN 13795 Suite of Tests Offered by Nelson Laboratories

The European standard, EN 13795, addresses the barrier properties, cleanliness, and strength of surgical drapes, gowns, and clean air suits used to protect patients from secondary infections in the surgical suite. The standard was approved in 2011, updated in 2013, and is the current standard today.

Nelson Laboratories is proud to announce that we are able to perform the eight tests required to meet the EN 13795standard. The addition of Hydraulic Burst Test and Resistance to Dry Microbial Penetration Test in 2016 completed the suite of tests offered by Nelson Laboratories to help manufacturers meet the requirements of the European standard. The following tests have been certified by ANAB to meet the requirements of ISO/IEC 17025:2005:

  • HPT220 Resistance to Dry Microbial Penetration
  • HPT210 Resistance to Wet Bacterial Penetration
  • BIO220 Bioburden
  • PSA120 Particle Shed Analysis
  • HPT110 Hydrostatic Pressure
  • HPT230 Hydraulic Burst Test
  • PHY150 Tensile Test, Dry
  • PHY155 Tensile Testing

Manufacturers of surgical drapes, gowns, and clean air suits who will be marketing their products in Europe need to make sure their product offerings meet the requirements outlined by EN 13795. Additionally, meeting the requirements of this standard is important for manufacturers who are looking to obtain the CE label for their products.

For more information, contact Nelson Laboratories’ Protective Barriers department ProtectiveBarriersStudyDirectors@NelsonLabs.com.