Reusable vs. Single-Use Devices: How Biocompatibility Testing Requirements Differ

Biocompatibility evaluation is essential for any medical device, but reusable and single-use devices present distinct challenges. Manufacturers must understand these differences to design appropriate test plans, meet FDA requirements, and ensure patient safety.

This article provides a detailed comparison of biocompatibility expectations for reusable and single-use medical devices in the U.S. market, explaining how the nature of device use influences risk assessments and testing strategies.

 

1. Understanding Device Categories: Reusable vs. Single-Use

• Single-use devices are intended for one-time application and disposal without cleaning or reprocessing (e.g., syringes, surgical gloves).

• Reusable devices are designed for multiple uses with validated cleaning, disinfection, and/or sterilization processes between uses (e.g., endoscopes, surgical reusable instruments).

This fundamental distinction heavily impacts biocompatibility risks and regulatory expectations.

 

2. Core Biocompatibility Principles for All Devices

Regardless of use type, every medical device must:

• Demonstrate that materials in direct or indirect contact with the patient are safe
• Assess risks related to device design, manufacturing processes, and material stability
• Follow a risk-based evaluation framework according to ISO 10993-1 and FDA guidance (Use of ISO 10993-1)

However, additional considerations arise specifically for reusable devices.

 

3. Unique Biocompatibility Challenges for Reusable Devices

Reusable devices face complex, cumulative risks over their lifetime:

3.1 Effects of Repeated Use

• Material degradation: Repeated cleaning and sterilization cycles can degrade polymers, coatings, or adhesives.
• Mechanical wear: Physical stresses during repeated use may alter material surfaces, leading to particle generation or changes in biocompatibility.

3.2 Cleaning and Disinfection Residues

• Residual chemicals from detergents or disinfectants may remain on device surfaces if cleaning protocols are inadequate.
• These residues can cause cytotoxicity, irritation, or sensitization reactions.

3.3 Validation of Reprocessing Procedures

The FDA expects manufacturers of reusable devices to:

• Validate cleaning, disinfection, and/or sterilization processes
• Demonstrate that these processes do not adversely impact material biocompatibility
• Simulate worst-case conditions (e.g., maximum number of use/reprocessing cycles)

Failure to demonstrate maintained biocompatibility across reprocessing cycles can lead to regulatory rejection.

 

4. Biocompatibility Expectations for Single-Use Devices

Single-use devices simplify some aspects of biocompatibility evaluation:

• No cumulative effects from multiple uses
• Sterilization validation focuses on ensuring a sterile product at point of use, without concerns about repeated exposure
• Device characterization must still be thorough, particularly regarding extractables and leachables from sterilization processes

However, high-risk categories (e.g., implants, blood-contacting devices) demand stringent biological evaluations even if single-use.

 

5. Testing Strategies: Key Differences

Material Stability

• Reusable Devices: Must demonstrate material stability over multiple reprocessing cycles to ensure that device properties and safety are maintained after repeated use.

• Single-Use Devices: Evaluated only in their pre-market condition; no need to assess effects of reprocessing.

Chemical Residues

• Reusable Devices: Require evaluation of residual cleaning agents and disinfectants that may accumulate after multiple cleanings.

• Single-Use Devices: Focus on sterilization residues present after a single manufacturing and sterilization process.

Simulated Use Testing

• Reusable Devices: Simulated worst-case reprocessing conditions must be tested to evaluate cumulative effects.

• Single-Use Devices: No simulated use testing required, as the device is not intended for reprocessing.

Reprocessing Validation

• Reusable Devices: Validation is mandatory to ensure cleaning, disinfection, or sterilization methods are effective and maintain device safety.

• Single-Use Devices: Not applicable, since the device is used once and discarded.

Biocompatibility Testing

• Reusable Devices: Testing must be performed after simulated reprocessing to assess any changes in biological safety.

• Single-Use Devices: Testing focuses on the original, unused state of the device.

 

6. Special FDA Expectations for Reusable Devices

For reusable devices, the FDA recommends:

• Worst-case chemical characterization: After maximum reprocessing cycles
• Extraction studies: Post-reprocessing for cytotoxicity, sensitization, and irritation evaluations
• Risk assessments: Specific to residual chemicals and potential for material degradation
• Detailed labeling: Clear instructions for reprocessing to maintain device safety

Not providing comprehensive post-reprocessing data may trigger Additional Information Requests (IRs) or denial of clearance.

 

7. Best Practices for Manufacturers

To streamline regulatory review and ensure robust biological safety:

• Plan for reprocessing impacts early: Design device materials and processes that can withstand cleaning/sterilization cycles.

• Validate worst-case scenarios: Conduct biological evaluations after multiple reprocessing cycles.

• Partner with experienced laboratories: Specialized labs can simulate reprocessing and perform post-reprocessing biocompatibility studies aligned with FDA expectations.

• Prepare integrated reports: Provide the FDA with a cohesive biological evaluation including pre- and post-reprocessing data.

 

Conclusion

Understanding the profound differences between reusable and single-use device biocompatibility requirements is critical for regulatory success in the U.S. market.
Reusable devices demand a more complex, lifecycle-focused evaluation strategy, including rigorous validation of cleaning and sterilization effects.
By strategically addressing these challenges, manufacturers can ensure device safety, reduce regulatory risks, and accelerate market entry.

Partnering early with a biocompatibility expert like NABI can make the difference between fast approval and costly delays.

 

About the Author: Prof. Łukasz Szymański

 

Prof. Łukasz Szymański is an expert in medical device biocompatibility testing, serving as the Chief Scientific Officer (CSO) of the ISO 17025-accredited and GLP-certified North American Biomedical Institute (NABI) and European Biomedical Institute (EBI). As a dedicated researcher and a key contributor to advancing safety standards in the biomedical field, Prof. Szymański plays an integral role in shaping scientific innovations and regulatory compliance within the industry.