When a project team at GlaxoSmithKline, King of Prussia, Pa. decided to count particles from light obscuration instrumentation while testing a new parenteral product formulation, concerned team members needed to know more about the particles counted but were in the dark with the technology on hand. Light obscuration yields a read-out of particles counted in the sample but it can’t differentiate one particle from another. “We couldn’t tell an air bubble from a foreign fiber or an agglomerated protein,” says Gregory Morrone, Associate Scientist, Biophysics, Biopharmaceutical Analytical Sciences for GlaxoSmithKline, “and it encounters difficulty counting the actual number of particles present since it can’t detect transparent or translucent particles.”


Left to right Gregory Morrone, Associate Scientist, Biophysics and
Wasfi Al-Azzam, Investigator, Biopharmaceutical Analytical Sciences,

GlaxoSmithKline, King of Prussia, Pa.

Counting particles in small samples of parenteral formulations has been performed primarily with visual inspection by holding a vial up to a light and subjectively grading the count as high, moderate or low, and secondarily with light obscuration instrumentation, which provides a total count of all particles detected greater than 10 and 25 microns. Both methods meet FDA requirements for counting particles under USP <1> and USP <788> yet many pharmaceutical formulators, analysts and quality control professionals such as those at GlaxoSmithKline are increasingly concerned about the shortcomings of the two methods. Many now realize that knowing exactly what particles may be hiding in their samples and how many of each type are vital to meeting strict quality demands, accelerating development timetables, minimizing risk and, ultimately, to the success of the product.

A team member with expertise in particle analysis reasoned an imaging particle analyzer that takes digital images of each individual particle detected in a sample would reveal the nature of the particles and assist in a better assessment of the product quality.  In an investigation of available technologies including several products including the FlowCAM® particle imaging and analysis system from Fluid Imaging Technologies, Yarmouth, Maine were evaluated by the project team. Some of these technologies demanded a host of adjustments, configurations, and set up time to yield images from the sample while requiring additional steps for qualification and validation. Some required substantially large volumes of very precious samples to obtain statistically significant data. The FlowCAM setup quickly, and with small samples, yielded high resolution images in real-time along with the particle size, count, shape and other measurement parameters. The FlowCAM detects opaque, translucent and transparent particles and automatically discerns one from the other with its proprietary pattern recognition software. “The entire project team was astounded to see actual images of aggregated proteins, longitudinal fibers, round, silicone oil droplets and air bubbles after years of being limited to simple counts and graphs,” says Morrone. “The FlowCAM allowed us to see exactly what was present, to determine why they were present and to understand whether the particles were related to the product formulation or to the sampling technique.”

Taking its measurements based on the actual images of each individual particle as opposed to taking measurements based on estimated particle counts and sizes, the FlowCAM offers unprecedented accuracy, which confers correspondingly high confidence in taking action based on the data. For particle analysis in the range of detection of 2.5 micron to 3 mm, the FlowCAM performed at a high level and yielded the highest quality images of any instrumentation. The team found it easy to input a sample, use the software and analyze the images and data via the companion VisualSpreadsheet© software, which enables users to filter and sort particle data based on almost any criteria required - even while a sample is running – and save them in libraries for future comparison. Its interactive spreadsheet format is intuitively simple. Individual images of interest may be selected with a mouse click while irrelevant images such as air bubbles are as easily deleted, yet the raw data always remains intact.”It’s very easy to use, very straightforward,” says Morrone.

In a matter of months, the project team had purchased the FlowCAM, a model VS-1 developed specifically for the type of laboratory analysis conducted in analyzing parenterals for proteinacous particles. The FlowCAM model VS-1 features an “autoimage mode” that automatically triggers its camera to capture an image each time a particle passes through the field of view in the flow cell. Though several more powerful, laser-enabled models are available with even greater capabilities and flexibility, the cost-savings in using the VS-1 offered added value.

Since installation in February 2010, the FlowCAM has been in continuous operation to automatically uncover any trends in the number and/or type of visible particles present in the samples.  With a tight product launch schedule, the project team is uncovering more information faster than ever and sharing it with colleagues in other departments around the world by emailing the images and data. “Quality control managers were amazed to see the actual particles on their monitors,” says Morrone, “and they’re more confident in the FlowCAM results.  The FlowCAM data is also being used to verify the accuracy of the data generated by visual inspection.


One of the key benefits of the FlowCAM is it detects and differentiates among
proteins, fibers, air bubbles and other particles.

Importantly but unexpectedly, the FlowCAM has also led to tangible cost savings. The light obscuration system requires at least a 25 ml sample volume to yield enough data to be considered statistically significant. By contrast, the FlowCAM requires only 1 ml

of sample to run an analysis. With samples often provided in 300 microliter ampoules, the FlowCAM has reduced the number of samples required from production from more than 800 per batch to three while also reducing sample handling and preparation requirements. “Now, we don’t need a large number of samples,” says Morrone, “The FlowCAM could save hundreds of thousands of dollars per year just in samples alone.”

The ability to see the actual particles in parenteral formulations, to see their morphology and to differentiate one type from another automatically marks an important advance in particle analysis. At GlaxoSmithKline, imaging particle analysis using the FlowCAM is being integrated into its testing program for development of protein-based parenteral drugs. With its full range of capabilities, the future application of such imaging particle analyzers may span from discovery and development to manufacturing.


About the Authors

Josh Geib is sales manager of industrial markets at Fluid Imaging Technologies, Yarmouth, Maine ( The company manufactures the FlowCAM® particle imaging and analysis system. Josh may be reached at 207.846.6100 or


Wasfi Al-Azzam is the leader of protein therapeutics higher order structure team at Biopharmaceutical Analytical Sciences in GSK-Biopharmaceuticals R&D