Medical device irritation testing is a critical component of biocompatibility evaluation and is subject to strict international and national regulatory oversight. It plays an essential role in ensuring that medical devices do not provoke adverse reactions such as redness, inflammation, or discomfort when in contact with the skin, mucosal membranes, or other body tissues.

According to the FDA regulations and international standards—specifically ISO 10993-10:2021, Biological evaluation of medical devices — Part 10: Tests for irritation and skin sensitization, irritation testing is conducted to assess local tissue responses after a device or its constituent materials are applied or implanted in the body.

Why Irritation Testing Is Required

Irritation reactions can result from residual chemicals, leachables, or contact with device surfaces. These reactions are distinct from allergic responses and are typically non-immune-mediated. Even short-term exposure can lead to irritation, which may manifest as:

  • Redness (erythema)
  • Swelling (edema)
  • Pain or burning sensations
  • Tissue damage in severe cases

Therefore, irritation testing helps mitigate patient safety risks and is a requirement for regulatory submissions, including premarket approvals (PMAs) and 510(k) notifications in the US, and CE marking in the European Union.

Testing Methodologies

A tiered testing strategy helps reduce unnecessary testing and ensures that only essential in vivo testing is performed. The updated ISO 10993-10 and ISO 10993-23 standards recommend the following approach:

1. Literature Review and Chemical Assessment
Manufacturers should begin by determining whether any known irritants are present using:

  • Tox databases (e.g., ECHA, PubChem, TOXNET)
  • ISO 10993-18 for chemical characterization

2. In Vitro Testing (New Approach Methodologies)

With a global push to reduce animal testing, in vitro models are increasingly validated and accepted:

  • Reconstructed human epidermis (RhE) models like EpiDerm™ and SkinEthic™
  • Bovine Corneal Opacity and Permeability (BCOP) assay for ocular irritation
  • Direct Peptide Reactivity Assay (DPRA) and other OECD-based protocol

These models provide reproducible results while reducing costs and ethical concerns.

3. In Vivo Testing
When in vitro models do not sufficiently characterize irritation risk, in vivo studies may be necessary:

  • Intracutaneous (intradermal) reactivity in rabbits
  • Primary skin irritation test
  • Ocular irritation testing (e.g., Draize test alternatives)

All testing must comply with good laboratory practices (GLP) and regulatory guidance from the FDA and European Medicines Agency (EMA).

4. Clinical Testing (as applicable)
In some cases, noninvasive human studies, such as human repeat insult patch testing (HRIPT), may be warranted to validate safety under real-use conditions.

Regulatory Landscape

The U.S. FDA has updated its guidance on the use of ISO 10993 standards, emphasizing a risk-based approach and encouraging the use of NAMs (New Approach Methodologies). Meanwhile, the European Union Medical Device Regulation (EU MDR) places stronger emphasis on biological safety evaluations throughout the product lifecycle, and the recently adopted ISO 10993-23:2021 provides clearer protocols for in vitro irritation tests.

Contract Laboratories Can Help with Medical Device Testing

Contract labs play a pivotal role in helping medical device manufacturers:

  • Conduct validated irritation testing following GLP and ISO/FDA requirements
  • Reduce time-to-market by integrating chemical characterization with biological evaluations
  • Transition to alternative test methods that support regulatory acceptance and ethical goals
  • Provide risk assessments and test strategies as part of regulatory submissions

These labs also ensure impartiality, advanced instrumentation, and scalable testing capacity, making them essential partners for quality assurance and regulatory compliance.

If you need FDA, ISO 10993-10, and ISO 10993-23 medical device irritation testing performed or are seeking an experienced third-party laboratory to assist with your regulatory submissions, simply submit a free test request. We’ll get the experts working on it right away!

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