A Rapid Sterility Method Using Solid Phase Cytometry for Cell-Based Preparations and Culture Media and Buffers.

In this article, we demonstrate a rapid sterility testing method for non-filterable cell-based preparations and its in-process control media/buffers. The selected rapid sterility test (RST) in this work is based on the ScanRDI® system, which detects fluorescently labeled microorganisms with solid-phase cytometry. ScanRDI® has been chosen due to its sensitivity for detecting viable microorganisms down to one microbial cell with a shorter time to detection compared with the compendial sterility test (CST) method. The RST was validated for a CAR-T cell-therapy product with 4 days of time to detection (TTD) and evaluated for in-process control of media/buffers with real-time detection method success according to USP <1223>, Ph. Eur. 5.1.6, and PDA Technical Report No. 33. The validation parameters included limit of detection and equivalence in routine operations, specificity, robustness, ruggedness, and repeatability. For the validation, a combination of pharmacopoeial ATCC strains as well as in-house isolates were used. In addition, the evaluation study of this RST for in-process control of media/buffers was assessed by performing the limit of detection and equivalence with four representative microorganisms. Where applicable, results were statistically evaluated to demonstrate equivalence and no significant difference of the rapid method as compared with the CST method have been detected. All acceptance criteria have been met, and the solid-phase cytometry technology was successfully validated as an alternative sterility test for cell-based preparations and for its in-process control of media/buffer.

Evaluation of a rapid microbiological method with a mixed culture biofilm model.

During the past decade, rapid microbiological methods (RMMs) have continued to make inroads into the pharmaceutical and medical device industries. This has led to the development of guidelines for the validation of alternative microbiological methods for both quantitative and qualitative applications. Many studies regarding RMMs have focused on testing performed with planktonic microorganisms. In some applications there is the possibility that microorganisms may also be present as biofilms. When evaluating an RMM, consideration should be given to the potential for biofilm formation within the context of the application and whether microorganisms derived from biofilm would influence the response of the method. This study reflects the evaluation of an RMM with both planktonic microorganisms and microorganisms derived from a mixed culture biofilm. LAY ABSTRACT: Many new rapid microbiological methods (RMMs) have been developed that have the potential to replace conventional microbiological methods in a wide range of applications including sterility testing, microbial enumeration, environmental monitoring, microbial identification, and other areas. Qualification of these new methods is frequently based on testing performed with planktonic (non-aggregated) microorganisms. However, microorganisms can aggregate together to form biofilms in both natural and manufacturing environments. Purified water systems in particular may be susceptible to the development of biofilms. Because the properties of microorganisms in a biofilm may differ from those in a planktonic state, qualification of an RMM with microorganisms derived from a relevant biofilm model may be appropriate depending on the application and the potential for biofilm formation. This study describes the evaluation of one such RMM, the Chemunex ScanRDI®, with both planktonic microorganisms and microorganisms derived from a mixed culture biofilm model.