With two PMT detection regions, the differences in non-biologic versus biologic emission spectra can be utilized to aid in the classification of
non-biologic materials as inert. As shown in Figure 2, a particle’s scatter and
fluorescence signals can be combined to create a three-dimensional map of
interferent and biologic particles. Advanced algorithms can then be utilized
to aid in the discrimination of biologic and interferent materials.
Figure 2: With a scatter
detector and two fluorescence detectors (PMTs),
an instantaneous microbial detection system
for water can create a
of biologic and interferent particles. Through
assessment of the three
different signals and an
algorithm, such a system
offers enhanced interferent discrimination capabilities.
monitoring, risk reduction, and process control
The use of an instantaneous microbial detection system for pharmaceutical water provides the ability to monitor bioburden continuously and in
real time, resulting in an increased potential for risk reduction and process control. Figure 3 shows representative data from the IMD-W™, a system designed with the OWBA requirements in mind, comparing IMD-W
biologic counts to culture plate results for three OWBA suggested organisms. This data covers a wide dynamic range and speaks to the potential
sensitivity and ability of such systems to monitor bioburden.
data from the
biologic counts as
compared to colony forming unit
method with TSA
The continuous data offered by these systems creates a robust histori-
cal dataset that is ideally suited for trending, particularly when compared
to episodic sampling with traditional methods. Sampling considerations
set forth in “USP<1231> Water for Pharmaceutical Purposes” recom-
mends monitoring pharmaceutical water systems at a frequency “suf-
ficient to ensure that the system is in control and continues to produce
water of acceptable quality.” 5 The general information chapter states it is
best to operate monitoring instrumentation in a continuous mode such
that a large volume of in-process data can be generated, and suggests the
use of trend analysis as an alert mechanism for loop maintenance. 5 A
combination of historical trending data and real-time results enable users
to identify an out-of-specification event or deterioration in microbiolog-
ical control significantly earlier than with traditional sampling methods.
By continuously monitoring the state of control, timely loop maintenance
can be performed if bioburden data trends upward, permitting further
risk reduction and an increased level of loop control. A real-time and his-
torical knowledge of control can also be important during a POU testing
deviation. 2 If POU testing is positive for microbial contamination, knowl-
edge and data to support a state of control may narrow the root-cause
investigation to the POU as opposed to contamination in the entire loop.
Regulatory guidance and calls from industry work groups support the need
for better tools for pharmaceutical water monitoring. New instantaneous
microbial detection systems based on LIF enable real-time bioburden monitoring, increased risk reduction, and process control for pharmaceutical
waters. Through continuous monitoring, these systems provide significant
historical data for robust trending and assessment of water loop bioburden levels, providing the means to monitor the level of control and react to
out-of-specification events in a much more timely manner than with traditional methods alone. Users stand to benefit through increased product quality and process understanding, energy savings, and risk reduction.
1. Cundell, A., Luebke, M., Gordon, O., Mateffy, J., Haycocks, N., Weber, J. W., et al.
(2013, May 16). On-Line Water Bioburden Analyzer Business Benefits Estimation.
Retrieved August 8, 2014, from http://www.miclev.se/fileadmin/user_upload/jen-nie/Online_Water_BioBurden_Analyzer_Business_Benefits.pdf .
2. Cundell, A., Gordon, O., Haycocks, N., Johnston, J., Luebke, M., Lewis, N.,
et al. (2013, May/June). Novel Concept for Online Water Bioburden Analysis:
Key Considerations, Applications, and Business Benefits for Microbiological Risk
Reduction. American Pharmaceutical Review, 26-31.
3. Cundell, A., Luebke, M., Gordon, O., Mateffy, J., Haycocks, N., Weber, J. W.,
et al. (2013, March 18). On-Line Water Bioburden Analyzer User Requirement
Specifications (URS). Document ID OWBA-DURS-2013-v1.3.
4. Cundell, A., Luebke, M., Gordon, O., Mateffy, J., Haycocks, N., Weber, J. W., et al.
(2013, April 24). On-Line Water Bioburden Analyzer Testing Protocol. Document ID
5. USP<1231> Water for Pharmaceutical Purposes. Pharmacopeial forum, Vol. 32;
United States Pharmacopeial Convention, Inc.: Rockville, MD, 2008.
6. Lakowicz, J. R. (2006). Principles of Fluorescence Spectroscopy (3rd ed.). New York:
Springer Science & Business Media.
7. Ammor, M. S. (2007). Recent Advances in the Use of Intrinsic Fluorescence for
Bacterial Identification and Characterization. Journal of Fluorescence, 17:455-459.
8. Rouessac, F., & Rouessac, A. (2013). Chemical Analysis: Modern Instrumentation
Methods and Techniques (2nd ed.). West Sussex: John Wiley & Sons.
Allison Scott is a senior applications engineer at BioVigilant, where
she has worked since 2010. She is now part of dedicated team of technicians and scientists comprising Azbil North America Research and
Development, Environmental Particle Solutions. She received her Ph.D.
in Materials Science and Engineering from the University of Arizona and
in Materials Chemistry from the University of Rennes.
BioVigilant, Instantaneous Microbial Detection, and IMD-W are
trademarks of Azbil BioVigilant, Inc., or its parent company, Azbil, in the
U.S. and elsewhere. www.biovigilant.com