Principles of Parametric Release: Emphasis on Data Collection and Interpretation

Parametric release, which relies on use of process data for product release, provides many benefits. However, adoption by the sterilization industry has been slow, with release typically involving biological indicator (BI) growth responses/ dosimetry readings. The current article highlights how the data provided by the process (described through examples for ethylene oxide [EO], vaporized hydrogen peroxide [VHP], and radiation) may be better used to inform parametric release implementation. The examples involving EO and VHP demonstrated the ability of the sterilization equipment to deliver validated parameters repeatedly after the load presented was validated. For instances in which load variability has not been addressed in performance qualification, BI testing or even measurement of EO concentration cannot reliably or fully inform the impact of such variance on the validated process. "Direct" monitoring of EO concentration is a current requirement in ISO 11135:2014. Nonetheless, the findings presented here show that EO and VHP concentrations can be determined by the calculated method, rendering the use of a concentration measurement probe somewhat superfluous. In alignment with European Union good manufacturing practice Annex 17, a key requirement of parametric release is to have sufficient data to demonstrate the repeatability of the validated process. Similar to gas technologies, radiation processing strives to implement parametric release but is limited by the currently available means of measuring all critical parameters, such as photon delivery.