Sterilization Modality Selection: Role of Sterility Assurance Subject Matter Expert.

Selection of a sterilization modality for a medical device is a critical decision that requires sterility assurance subject matter experts (SME)s to work collaboratively with various company functions. The sterility assurance SME is responsible and accountable for the sterilization modality decision for a product. The modality selection process starts with the sterility assurance SME partnering with research and development to ensure that the sterilization modality allows the device to deliver its intended function in patient care. After the sterilization modality is selected, the sterility assurance SME needs to work with other partners, including quality, supply chain/logistics, operations, and regulatory, to ensure that the selected sterilization modality is appropriately integrated into the end-to-end process. Collaborative partnerships between sterility assurance experts and key partners regarding sterilization modality selection reduce the potential for negative impacts within the end-to-end sterility assurance process, including impacts on product functionality, increased regulatory approval timelines, and inefficiencies and risks throughout the supply chain. This article describes aspects of a comprehensive approach to sterilization modality selection, including critical information necessary to address each of the key considerations.

Sterility Assurance Across-Sectors-New Paradigms and Tools.

The sterility assurance community is facing significant challenges. A relatively recent challenge is the pressure on manufacturing supply chains resulting from the limited availability of capacity for terminal sterilization of healthcare products. The current challenge is finding solutions for innovative new products, especially biologics and combination products, that offer great promise for patients around the world. This challenge will become more prevalent in the future as products advance. This article frames new paradigms and tools being developed to address these challenges. Foundational principles and current realities from each sector are reviewed so that sterility assurance professionals have a solid base from which to build strategies.

Research: Dry Heat Processing of Single-Use Respirators and Surgical Masks.

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2, has challenged healthcare providers in maintaining the supply of critical personal protective equipment, including single-use respirators and surgical masks. Single-use respirators and surgical masks can reduce risks from the inhalation of airborne particles and microbial contamination. The recent high-volume demand for single-use respirators and surgical masks has resulted in many healthcare facilities considering processing to address critical shortages. The dry heat process of 80°C (176°F) for two hours (120 min) has been confirmed to be an appropriate method for single-use respirator and surgical mask processing.

Use of Overkill Half-Cycle Qualification Data to Support Reduction of Exposure Time in Validated Ethylene Oxide Sterilization Cycles.

This article details the evaluation conducted for the potential to reduce ethylene oxide (EO) exposure times using data from currently validated EO sterilization cycles. The candidate cycles used the overkill half-cycle approach detailed in Annex B of ANSI/AAMI/ISO 11135:2014. The overkill half-cycle approach is conservative and has been the method of choice with medical device manufacturers because of its ease of understanding. The analysis presented provides an understanding of the extent of this conservative nature. Based on the analysis, exposure time can be reduced and rapidly implemented. The reduction in the exposure time may improve the product EO residuals and allow for additional time for the EO processing chamber to be utilized and/or for additional off-gassing for the product, if needed.

Radiation Sterilization: Dose Is Dose.

In the radiation sterilization arena, the question often arises as to whether radiation resistance of microorganisms might be affected by the energy level of the radiation source and the rate of the dose delivered (kGy/time). The basis for the question is if the microbial lethality is affected by the radiation energy level and/or the rate the dose is delivered, then the ability to transfer dose among different radiation sources could be challenged. This study addressed that question by performing a microbial inactivation study using two radiation sources (gamma and electron beam [E-beam]), two microbial challenges (natural product bioburden and biological indicators), and four dose rates delivered by three energy levels (1.17 MeV [gamma], 1.33 MeV [gamma], and 10 MeV [high-energy E-beam]). Based on analysis of the data, no significant differences were seen in the rate of microbial lethality across the range of radiation energies evaluated. In summary, as long as proof exists that the specified dose is delivered, dose is dose.

Radiation Dose Audit Failures: Truth and Consequences.

The validation of a radiation sterilization dose involves an initial sterilization dose determination as well as maintenance of that sterilization dose. The procedures for maintenance of the sterilization dose typically include the periodic use of two types of tests: bioburden and dose audits. The details for the procedures are outlined in the ISO radiation sterilization standards. These documents also provide guidelines for recommended actions in response to the results of the two tests. The results for the dose audit are based on the number of positive tests of sterility (TOS) for products that have been irradiated at a verification or experimental dose. When the dose audit yields TOS positives, it is often thought that they indicate a sterilization failure and nonsterile product. The belief that any TOS positive is a failure is an incorrect assumption because of the statistical basis used for the determination of the sterilization dose. This article will outline the truth of what dose audit TOS positives mean in terms of the sterility assurance of product, as well as the consequences of TOS positives.

Sterilization of products contaminated with Pyronema domesticum.

Product recalls due to non-sterility occurred between 1993 and 1994 among manufacturers that were sterilizing cotton products sourced from China using ethylene oxide (EO). The primary contaminant was identified as a pyrophilous mold from the class Discomycetes, Pyronema domesticum. Multiple references suggest this organism has special needs for reproducing and maintaining the two assumed resistant stages of this organism (ascospores and sclerotia). Sterilization resistance studies were performed using a China-sourced cotton product that was naturally contaminated with P. domesticum. These studies showed the organisms to have: 1) a low resistance to moist heat sterilization at 250 degrees F (121 degrees C); a resistance to radiation no greater than that predicted by the bioburden-based resistance model (i.e., Population C) used for dose determination Method 1 described in ANSI/AAMI/ISO 11137-2:2006--Sterilization of health care products--Radiation--Part 2: Establishing the sterilization dose; and 3) a high resistance to EO processing.