Understanding the Non-Equivalency of Bio-Fluorescent Particle Counts versus the Colony-Forming Unit.

Adopting emerging microbiological methods is often desirable because it enables more advantageous, real-time monitoring practices. However, when the newer method measures contamination based on a different detection principle and provides results that are based on different units of measure, a paradigm shift is necessary. That shift can be one of the most difficult challenges in any such project and requires careful consideration. In this article, we explore the challenges presented by the bio-fluorescent particle counting (BFPC) technology, when considering that the traditional colony-forming unit (CFU) is the gold standard that any change is measured against. We examine why attempts to correlate newer units of measure used by biofluorescent particle counters, namely the auto-fluorescent units (AFUs), to the traditional CFUs are not necessarily appropriate. The article explores in depth why there is no consistent correlation factor between the two units of measure, and why that should not be a barrier to fully leveraging, implementing, and using such modern technologies in routine monitoring.

Rapid Sterility Test Systems in the Pharmaceutical Industry: Applying a Structured Approach to Their Evaluation, Validation and Global Implementation.

The current compendial sterility test has a 14-day incubation time and is often the time-limiting step in the Assess and Release Process of pharmaceutical products. There is an ever-increasing number of technologies available on the market that have benefits in addition to faster Time to Result, such as standardization and automation of readout (eliminating analyst subjectivity) and improved data integrity (including eliminating the need for contemporaneous verification of the result by another analyst). Regulators have been encouraging the pharmaceutical industry to adopt these innovative systems; however, it has taken a considerable time before receiving the first approvals from various health authorities (including both the European Medicines Agency and Food and Drug Administration) for the use of an alternative and rapid sterility test for the release of sterile drug product lots. This article describes a systematic 9-step approach to the evaluation, equipment qualification, validation, and deployment of alternative sterility tests that can be applied by pharmaceutical companies wanting to take advantage of the numerous benefits of alternative sterility tests. Two case studies are presented to illustrate the validation and implementation approach, including statistical methods. Although most of the steps toward implementation are aligned, the validation and transfer have been approached differently for each of the case studies because of differences in the chosen technology as well as independent company internal decisions to comply with validation guidelines. However, both case studies show successful implementation of an alternative sterility test for sterile drug products with an ∼50% reduced incubation time.

Challenges Encountered in the Implementation of Bio-Fluorescent Particle Counting Systems as a Routine Microbial Monitoring Tool.

The transition from traditional growth-based microbial detection methods to continuous bio-fluorescent particle counting methods represents a paradigm shift, because the results will be non-equivalent in terms of microbial counts, and a continuous, rather than periodic, data stream will be available. Bio-fluorescent particle counting technology, a type of rapid microbiological method, uses the detection of the intrinsic fluorescence of microbial cells to enumerate bioburden levels in air or water samples, continuously. The reported unit is commonly referred to as an autofluorescence unit, which is not dependent upon growth, as is the traditional method. The following article discusses challenges encountered when implementing this modern technology, and the perspective from a consortium of four industry working groups on navigating these challenges.

A Systematic Approach for the Evaluation, Validation, and Implementation of Automated Colony Counting Systems.

For several years, automated colony counting systems have been available with varying degrees of automation. Ever more sophisticated instruments are now increasingly used in microbiological laboratories of pharmaceutical quality control. In addition to the colony counting device, the instruments are now also equipped with robotic systems performing the entire handling of the petri dishes, e.g., automated internal transportation of petri dishes from the incubator chamber to the instrument's enumeration device and back. Moreover, the subjective evaluation of microbial enumeration tests by analysts is replaced with a more accurate and precise process. This leads to significant improvements to data integrity compliance. Automated colony counting systems also often enable cost reduction in the microbiological laboratory, e.g., by not requiring a contemporaneous verification by a second analyst. They also enable direct integration of count data into an existing laboratory information management system, reducing the hands-on time, costs per test and also preventing human errors caused by manual transcription. Altogether, these instruments will lead to improved monitoring and assurance of control of biopharmaceutical processes and manufacturing environments, as well as shortened cycle times in the supply chain. Regulators are encouraging the biopharmaceutical industry to adopt these innovative systems. For example, this year a BioPhorum member company received the first health authority approvals from EU, US, CH, Canada, Australia, and China for the use of automated colony counting systems for in-process bioburden testing and the release of drug substance lots, with an incubation time reduced by about 50%. Although these approvals are for release testing of drug substance lots, the instruments can also be used for environmental monitoring, testing of water samples, etc. This article describes a systematic 9-step approach to the evaluation, equipment qualification, and deployment of automated colony counting systems, which can be applied by biopharmaceutical companies wanting to take advantage of their numerous benefits.

Savitzky-Golay smoothing and differentiation for polymerase chain reaction quantification.

In quantitative PCR (qPCR), replicates can minimize the impact of intra-assay variation; however, inter-assay variations must be minimized to obtain a robust quantification method. The method proposed in this study uses Savitzky-Golay smoothing and differentiation (SGSD) to identify a derivative-maximum-based cycle of quantification. It does not rely on curve modeling, as is the case with many existing techniques. PCR fluorescence data sets challenged for inter-assay variations (different thermocycler units, different reagents batches, different operators, different standard curves, and different labs) were used for the evaluation. The algorithm was compared with a four-parameter logistic model (4PLM) method, the Cy0 method, and the threshold method. The SGSD method compared favourably with all methods in terms of inter-assay variation. SGSD was statistically different from the 4PLM (P = 0.03), Cy0 (P = 0.05), and threshold (P = 0.004) methods on relative error comparison basis. For intra-assay variations, SGSD outperformed the threshold method (P = 0.005) and equalled the 4PLM and Cy0 methods (P > 0.05) on relative error basis. Our results demonstrate that the SGSD method could potentially be an alternative to sigmoid modeling based methods (4PLM and Cy0) when PCR data are challenged for inter-assay variations.