Term
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Definition
| the science and technology of small particles |
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Term
| Differentiate projected diameter, feret diameter, and martin diameter |
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Definition
projected- circle
feret- two ends
martin-bisect |
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Term
| What is used to measure geometric or projected diameter? |
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Definition
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Term
| What is used to measure volume diameter? |
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Definition
| laser diffraction, light obscuration, and coulter counter |
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Term
| What is used to measure stoke's diameter? |
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Definition
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Term
| What is used to measure equivalent surface diameter? |
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Definition
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Term
| What is used to measure aerodynamic diameter? |
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Definition
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Term
| How much(percentage) of the particles are included after 1, 2, and 3 standard deviations? |
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Definition
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Term
| What are the advantages and disadvantages of using a microscope? |
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Definition
ADV- simple, can see aggregates, asses dryness and morphology
DIS-slow, expensive for some scopes |
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Term
| How is sieving performed? |
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Definition
Load powder onto sieve nest and shake for a predetermined time. Weigh each fraction
expressed as under/over size and mean particle size |
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Term
| How is geometric deviation(σg) calculated? |
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Definition
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Term
| Which is used for therapeutic dosing: weight or number? |
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Definition
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Term
| What two forces determine the terminal velocity used in the sedimentation process? |
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Definition
| gravitational and drag forces |
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Term
| What is terminal velocity proportional to? |
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Definition
| the square of its diameter |
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Term
| What is difference between Laminar flow and turbulent flow? |
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Definition
Laminar flow is no resistance and has an Re number <0.2
turbulent is >0.2 |
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Term
| What are the disadvantages to sedimentation? |
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Definition
-assumes all particles have same density
-assumes they are all spheres
-does not detect aggregates |
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Term
| How is the Andreasen Pipette used for sedimentation determination of stoke |
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Definition
-suspension of 1-2% particles introduced and allowed to settle
-samples taken at different intervals
-fluid evaporated from each sample and then weighed
-cumulative weight undersize used to calculate mean particle size |
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Term
| What is the general concept of determination of volume diameter? |
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Definition
| Particle suspended or aerosolized in container with a sensing mechanism that has an output used to measure particle volume |
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Term
| What are the three types of sensing mechanisms for determining volume diameter? |
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Definition
-laser diffraction
-light obscuration(coulter counter)
-light scattering (Brownian motion) |
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Term
| Which of the three methods for determining volume diameter assume spherical particle shape? |
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Definition
| Coulter Counter(light obscuration) and laser diffraction |
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Term
| What are the disadvantages of volume diameter methods? |
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Definition
| cant discriminate aggregates, expensive, training |
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Term
| How do you calculate specific surface area of spherical particle? |
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Definition
SA=6/(Density*Diameter)
Density and diameter must both be in the same units cm or um |
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Term
| What equation is gas adsorption related to? |
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Definition
BET
brunauer emmet equation |
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Term
| What equation is air permeability(inertial impaction) related to? |
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Definition
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Term
| What are the 4 general powder properties? |
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Definition
surface area
porosity
density
flow properties |
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Term
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Definition
| Measure of the void spaces in a powder |
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Term
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Definition
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Term
| What factors does porosity influence? |
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Definition
density
flow properties
compressibility
dissolution rate
aerodynamic properties(for inhalables) |
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Term
| What are the four types of pores in solids? |
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Definition
-homogeneous size/shape/distribution (some connected)
-diff. size/shape homogeneous distribution (no connection)
-irregular shapes, surface only (few connected)
-irregular shapes, surface and interior (MOST connected) |
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Term
| Which will penetrate deepest pores better: gases or liquids? |
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Definition
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Term
| What are the four expressions of density? |
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Definition
-True density
-Granule density
-Bulk density
-Tapped Density |
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Term
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Definition
density of material without pores or inter-particulate spaces
measured with pycnometer based on archimides principle |
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Term
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Definition
| Density of material with pores considered >10um |
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Term
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Definition
| Density derived from the volume occupied by an UNPACKED mass of powder |
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Term
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Definition
| Density derived from the volume occupied by a PACKED mass of powder |
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Term
Which densities are the most accurate?
*Density becomes greater with accuracy |
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Definition
1)True Density(greater than any surface density)
2)Tapped Density
3)Bulk Density |
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Term
| What is Archimedes' principle? |
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Definition
The weight of the displaced fluid is directly proportional to the volume of the displaced fluid
**applied to liquid pycnometers
(gas is boyle's law) |
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Term
| How do you calculate true density? |
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Definition
p=m/(m+v-m')
m-mass of solid
v-volume of pycnometer
m'-mass of pycnometer with water+solid |
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Term
| How do you calculate bulk density (apparent density)? |
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Definition
mass/volume taken up by the particles and air
measured in height but gives volume |
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Term
| How do you calculate porosity(ϵ)? |
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Definition
| ϵ=1-(bulk density/true density) |
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Term
| What are the number of taps recommended when performing tapped density? |
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Definition
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Term
| What are the flow properties of powder influenced by? |
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Definition
-size and distribution
-shape
-porosity
-density
-surface texture |
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Term
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Definition
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Term
| What are the six problems in manufacturing dealing with flow properties of solids? |
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Definition
| arching, rat-holing, hang up, flooding, segregation, difficulty getting level measurement |
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Term
| What are the four inter particulate forces in powders? |
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Definition
Capillary Forces(moisture)
Van der Waals Forces
Mechanical interlocking
Electrostatic Charge |
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Term
| What are the relative magnitudes of the interparticulate forces? |
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Definition
van der waals (smallest)
Capillary forces
adhesive binding and solid bridging(largest) |
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Term
| What is Carr's compressibility index used for? |
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Definition
Measure powder flow
relationship of bulk and tapped densities |
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Term
| How do you calculate CCI? |
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Definition
CCI=(Pt-P')/Pt *100%
No units |
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Term
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Definition
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Term
| What are the relative angle of reposes for cohesive and free flowing? |
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Definition
Cohesive=larger angle of repose(steeper)
Free flowing= Smaller |
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Term
| What are the ways to regulate powder flow of fine powders? |
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Definition
granulation(make larger?)
formulate into particles
absorb into larger particles
MAKE LARGER |
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Term
| What are the ways to regulate powder flow of large(granule) powders? |
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Definition
add fines
add glidants(starch, talc, Mg stearate) |
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Term
| What method would you use to determine particle size for injectable solution? |
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Definition
light scattering
electron microscope(scanning and transmission) |
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Term
| What method would you use to determine particle size for dry powder inhaler? |
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Definition
laser diffraction
scanning e microscope |
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Term
| What method would you use to determine particle size for granules for reconstitution? |
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Definition
optical microscope
sieving |
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Term
| What method would you use to determine particle size for powders to fill capsules? |
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Definition
optical microscope
sieving |
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Term
| What method would you use to determine particle size for tablet excipients? |
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Definition
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Term
| What would cause particles to not flocculate properly? |
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Definition
too large
reduce particle size |
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