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Biomedical
Application Case Study -
Medical Device
Research & Development |
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Digital Imaging Cuts
Through
the Mist of Nasal Spray R&D |
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"Muro scientists wanted a system that would
record the spray pattern and allow them to quantify an unaltered cross section of the
spray pattern and its particles. The system would allow scientists to better match the
viscosity, or fluid properties of the medicine they are spraying, to the geometry of the
pump. This information could create savings in time and money during the R&D
process."
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By:
Dino J. Farina
President
Image Therm Engineering, Inc.
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Muro Pharmaceutical, a leading
aerosol nasal spray manufacturer based in Tewksbury, Mass., needed a new testing method to
characterize nasal inhaler sprays. The target system would serve its R&D needs,
delivering a large volume of fluid mechanic data, and hopefully exceed current Food and
Drug Administration (FDA) testing standards.
To meet that goal, scientists at Muro and Image Therm Engineering
(Waltham, Mass.), a scientific imaging and engineering design firm, have developed a
non-intrusive system to characterize nasal inhaler spray using high-speed digital imaging.
The system, called SprayVIEW, helps drug designers at Muro
optimally match and fine-tune the geometry and performance of its nasal inhaler spray
pumps to the fluid properties of their medicinal solutions.
Fluid dynamic characterization of the aerosol spray from nasal
inhalers is crucial in evaluating the inhaler's ability to deliver medicine to people
suffering from respiratory ailments. Spray characterization is also an important part of
the regulatory submission necessary for FDA approval of new nasal inhaler-based products
and designs.
For many years, Muro scientists have been using a solid
thin-layer chromatography (TLC) method. A TLC plate is positioned at a fixed height above
the end of the inhaler's nozzle. When the inhaler is pressed, spray is deposited on the
plate. The plate is coated with material that glows when it is exposed to UV radiation.
Using calipers and pencils to draw an outline of the patterns on the plate, scientists
extrapolate data from the patterns formed by the flying particles on the plates.
Muro scientists were not satisfied with the data delivered by
this test. One problem arises from the mechanics of the test. With an impermeable plate
placed above the spray, the flow structure changes radically. Spray droplets bounce off
the plate and back into the flow of the spray, altering the spray pattern and flow. The
presence of the TLC plate radically alters the natural fluid dynamics of the spray,
causing it to switch from a free aerosol jet to an impinging jet. Also, measurements of
the spray pattern are very sensitive to the operator's judgment and prone to low
reliability. Finally, the technique is restricted to measurements of the spray pattern
only; it cannot be used to investigate any time-evolving or geometrical properties of the
spray such as the divergence angle.
Muro scientists wanted a system that would record the spray
pattern and allow them to quantify an unaltered cross section of the spray pattern and its
particles. The system would allow scientists to better match the viscosity, or fluid
properties of the medicine they are spraying, to the geometry of the pump. This
information could create savings in time and money during the R&D process. |
- Top of the
page - |
Imaging Integration
Muro chose Image Therm Engineering, an
integrator of thermal engineering, fluid dynamics and scientific imaging solutions, to
develop its testing system. Image Therm developed a system consisting of four primary
components: a Kodak [Note - Redlake MASD, Inc., has acquired the Motion Analysis Systems Division From Eastman Kodak]; a Lasiris (Quebec, Canada) Magnum 4000 continuous wave diode
laser sheet; an electro-pneumatic spray pump from InnovaSystems Inc., (Pennsauken, N.J.);
and SprayVIEW system software built using National Instruments'(Austin, Texas) LabVIEW and
IMAQ Vision software.
The system works by projecting a laser sheet through a specified
axial cross section of the spray. Muro Pharmaceutical and Image Therm Engineering
implemented a completely non-intrusive, optical-based design for the system that would be
capable of capturing the time evolution of the spray for complete geometrical (divergence
angle) and pattern (cross-sectional uniformity and ellipticity) characterization.
The illuminated cross section is captured at a rate of 500 frames
per second (fps). The imaging software collects the data, creating various types of
composite images for analysis. These composite images allow further analysis of the
geometric properties of the spray. This approach gives Muro scientists visual and
quantitative information previously unavailable using the TLC plates. |
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System Expectations
Muro Pharmaceutical and Image Therm Engineering combined their expertise in nasal spray
drug development, fluid mechanics, high-speed imaging and image processing software to
develop the novel SprayVIEW Spray Characterization System. The system allows spray-based
drug developers to characterize the time-evolution, particle distribution, and divergence
angle of spray patterns quickly and effectively. The system's non-intrusive, optical-based
design provides significantly improved measurement performance over the currently accepted
TLC-plate based testing technique. The highly modular hardware and software components
allow easy customization to meet the needs of a variety of spray-testing applications both
in R&D and production environments. SprayVIEW is currently being used as a research
and development tool for current and pending nasal spray-based medications while Muro
Pharmaceutical and Image Therm Engineering seek FDA approval for the system's novel
measurement and analysis techniques. |
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Cameras -
Cameras typically used in
biomedical applications - |
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| Biomedical Video Clip |
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