Using the ISO 10993-18 to Guide Chemical Characterization

In this interview, AZoM talks to Kevin Rowland, Laboratory Manager at Jordi Labs, about the ISO 10993-18 guidance document describing best practices for performing chemical characterization.

1. Could you give our readers an overview of Jordi Labs and the work you do?

Jordi Labs is a premier analytical laboratory specializing in chemical analysis of materials.  We assist our customers in preparing submissions for pharmaceutical packaging, medical devices and food contact materials.

Our expertise in chromatography and mass spectrometry, along with extensive expertise in polymer and material science gives us a unique perspective on these regulatory analyses. We can also help with deformulation, manufacturing problem solving, expert witness services, and many other analytical solutions.

2. What are the important considerations before submitting a medical device for testing?

When submitting a device for chemical characterization, data relating to the composition (along with any manufacturing aids) should be gathered in as much detail as possible.  This information will inform any chemical characterization required and allows assessment of the materials used for the possibility that highly toxic (cohorts of concern) compounds may be present.

The most current version of ISO 10993-18 gives further emphasis on the collection of this type of information from manufacturing procedures and suppliers prior to testing.  It is also important to include all available information relating to the use conditions and patient exposure of a device submitted for analysis.  With all of this information, our regulatory specialists can help ensure the study is well designed.

Image Credit: Jordi Labs

3.  What is ISO 10993-18 and how does it guide medical device companies in assessing chemical risks?

ISO 10993-18 is a guidance document that describes best practices when performing chemical characterization for toxicological risk assessment of medical devices.  The document provides guidance relating to identification and toxicological risk assessment of organic materials that are extractable from a medical device and therefore may result in patient exposure.

At Jordi Labs, we have developed industry-leading processes to ensure accurate identification and quantification of extractables and leachables.  This is crucial in providing thorough toxicological risk assessment.

4.  How has ISO 10993-18 been expanded and how does the revision bring ISO 10993-18 more in line with other standard procedures?

In addition to the emphasis placed on gathering information on raw materials and manufacturing, as already mentioned, the document has been expanded to bring more harmony between the regulatory documentation.  Other parts of the ISO 10993 series (ISO 10993-1, ISO 10993-12 and ISO 10993-17) are referenced as well as concepts from ISO/TS 21726.

6. How have the definitions of analytical practices changed?

In addition to further defining some of the practices used, the document adds ‘simulated use conditions’ in the context of leachables analysis.  This clarification of the leachables condition allows for use of simulating conditions when it is not possible to replicate in the laboratory conditions equivalent to those that are used in a clinical setting.

Also, testing approaches often encountered that are unique to chemical characterization, like digestion and dissolution are clarified in the updated guidance.

7. What are the benefits of the new definitions which have been added to ISO 10993-18?

The definitions that have been added, provide some needed clarity in the procedures used during the chemical characterization of a medical device. Definitions are provided clarifying semi-quantitative, estimated quantitative and quantitative methods.

These definitions address the issue of response factor variation, a significant contributor to error in the chemical characterization of medical devices.  Jordi Labs has published a series of peer-reviewed publications describing the problems associated with response factor variation, and the methods that we use to solve them.

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8. How will the updates change the chemical characterization process?

A number of changes are expected based on the new guidance. Triplicate extractions are now recommended specifically in the revised guidance.  Other changes will affect the conditions which trigger when an E&L study is recommended.

Qualification of analytical methods is now required and quantitative methods also have been clarified highlighting issues such as response factor variation and limitations of instrumental dynamic range.

9. How will the updates help to overcome challenges such as the underreporting of compounds?

The new revision of the standard gives additional clarification on setting the analytical evaluation threshold (AET).  The document also introduces an uncertainty factor (UF) which is applied to the AET.  The UF is applied to address the issue of response factor variation.  For several reasons, it is common practice in studies to rely on the semi-quantitative estimation of analyte concentrations.

This process relies on the instrumental response from surrogate analytical standards which is applied to observed extractables.  Because these compounds may have different response factors (amount of response per unit concentration), there is error introduced.

The UF is applied such that the AET is adjusted based on the expected magnitude of this error, preventing underreporting of compounds that have low response factors.  It is also very important that the methods used are designed to mitigate response factor variation.  Failure to do so results in high UF values, which in turn cause very low AET values.

In some cases, extensive preparation of extracts or thresholds that cannot be practically reached can result.  To make matters worse, response factor variation directly impacts the accuracy of estimated quantities of extractables observed.  This makes it doubly important that the laboratory fully understands the response factor problem and develops procedures to minimize it.

For more information, please visit: https://jordilabs.com/

About Kevin Rowland

Kevin Rowland, M.S. received his bachelor’s degree in ceramic engineering in 2001 followed by a master’s degree in 2003 in materials science and engineering both from Alfred University.  He then received a master’s degree in chemistry from Brown University under Dr. Brian Moulton in 2008 with research focusing on molecular self-assembly.  Kevin has been at Jordi Labs for 9 years and has served as team leader for the GCMS and LCMS groups.  His work has focused on interpretation of high-resolution accurate mass MS data for identification of non-target, unknown compounds.  He is currently serving as Laboratory Manager.