Residual Hydrogen Peroxide Determination

We assess hydrogen peroxide residues remaining on medical devices following H2O2 sterilisation processes to assess biocompatibility and patient safety.

Our Accreditations

Applicable Standards

BS ISO 22441:2022 – Sterilisation of health care products. Requirements for the development, validation and routine control of a low-temperature hydrogen peroxide sterilization process for medical devices. Directs that appropriate limits for sterilisation process residuals should be established using 10933-17.

BS EN ISO 10993-1:2025 - Biological evaluation of medical devices. Guidelines for the assessment of biological hazards and general principles governing the biological evaluation of medical devices within a risk assessment framework.

BS EN ISO 10993-17:2023+A1:2025 – Toxicological risk assessment of medical device constituents. Provides a process and requirements for the toxicological risk assessment of medical device constituents, as applied to chemical characterisation information derived in line with BS EN ISO 10993-18.

BS EN ISO 10993-18:2020+A1:2023 – Chemical characterisation of medical device materials within a risk management process. Provides a framework for the identification and quantification of the constituents of a medical device, allowing for the identification of biological hazards. This includes residues from chemical substances introduced during sterilisation.

Residual Hydrogen Peroxide Testing

We quantify extractable hydrogen peroxide residues present on or in medical devices having undergone H2O2 sterilisation and to assess if those residues represent a toxicological risk.

As outlined in ISO 22441 section 5.4.5, quantification of residual hydrogen peroxide present on/in healthcare products after the sterilisation process must be perfomed using a validated method. The data is then used to complete a health-based risk assessment in accordance to ISO 10993-17 in order to establish scientifically justified safety limits.

ISO 10993-17 and 18 provide guidelines for test sample selection and treatment, extraction approach, construction of an appropriate toxicological risk assessment, derivation of exposure limits and the classification of process residues determined to represent a toxicological risk or else fall below harmful levels.

Frequently Asked Questions

What are residuals and why do they pose a risk?

Residuals are traces of chemicals or by-products of chemicals that remain in or on a product that has been treated with the chemical in some form. For medical devices, this can occur during reprocessing cleaning, disinfection and sterilisation steps which involve various chemical agents. The toxicological risk of potential chemical residuals needs to be determined to ensure devices are safe to use on patients. The risks of residuals are assessed based on the type of medical device and what part of the body it is likely to be in contact with, the duration of the contact, and the sensitivity of the patient population.

Is proving microbial kill enough when validating a H2O2 sterilisation process?

No. The ISO 22441 standard mandates that the validation must demonstarte a sterility assurance level as well as chemical safety through a toxicological risk assessment. Testing of residuals and establishing safety limits is crucial in completing the process validation.

How are hydrogen peroxide residuals quantified?

Residuals need to be extracted from the medical device before quantifying. Guidance for extraction methods can be found in ISO 10993-18. Quantification methods of hydrogen peroxide residuals include spectrophotometric analysis e.g. using the ferrous-oxidation xylenol-orange (FOX) assay, or for rapid qualitative/semi-quantitative determination, test strips can be used.

What are the advantages of hydrogen peroxide over ethylene oxide?

The chemical risks of ethylene oxide (EtO) are much greater than hydrogen peroxide due to it being carcinogenic. The aeration phase of an EtO sterilisation cycle are longer in order to ensure minimal residues remain on devices. Hydrogen peroxide in comparison breaks down into water and oxygen and does not require a lengthy aeration phase.

Is VHP an approved method of sterilisation by the FDA?

Yes. With the FDA recognition of the ISO 22441 standard, VHP sterilisation is now listed as an Established Category A sterilisation method by the FDA. This makes it easier for manufacturers who are considering switching from EtO sterilisation to VHP.