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Ceutics II Test 1
Part 2 (Micromeritics)
58
Other
Professional
02/09/2012

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Cards

Term
What is micromeritics?
Definition
the science and technology of small particles
Term
Differentiate projected diameter, feret diameter, and martin diameter
Definition
projected- circle
feret- two ends
martin-bisect
Term
What is used to measure geometric or projected diameter?
Definition
microscopy and sieving
Term
What is used to measure volume diameter?
Definition
laser diffraction, light obscuration, and coulter counter
Term
What is used to measure stoke's diameter?
Definition
sedimentation
Term
What is used to measure equivalent surface diameter?
Definition
gas adsorption
Term
What is used to measure aerodynamic diameter?
Definition
inertial impaction
Term
How much(percentage) of the particles are included after 1, 2, and 3 standard deviations?
Definition
68
95.5
99.7
Term
What are the advantages and disadvantages of using a microscope?
Definition
ADV- simple, can see aggregates, asses dryness and morphology

DIS-slow, expensive for some scopes
Term
How is sieving performed?
Definition
Load powder onto sieve nest and shake for a predetermined time. Weigh each fraction

expressed as under/over size and mean particle size
Term
How is geometric deviation(σg) calculated?
Definition
50% size/16% undersize
Term
Which is used for therapeutic dosing: weight or number?
Definition
weight
Term
What two forces determine the terminal velocity used in the sedimentation process?
Definition
gravitational and drag forces
Term
What is terminal velocity proportional to?
Definition
the square of its diameter
Term
What is difference between Laminar flow and turbulent flow?
Definition
Laminar flow is no resistance and has an Re number <0.2

turbulent is >0.2
Term
What are the disadvantages to sedimentation?
Definition
-assumes all particles have same density
-assumes they are all spheres
-does not detect aggregates
Term
How is the Andreasen Pipette used for sedimentation determination of stoke
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
Term
What is the general concept of determination of volume diameter?
Definition
Particle suspended or aerosolized in container with a sensing mechanism that has an output used to measure particle volume
Term
What are the three types of sensing mechanisms for determining volume diameter?
Definition
-laser diffraction
-light obscuration(coulter counter)
-light scattering (Brownian motion)
Term
Which of the three methods for determining volume diameter assume spherical particle shape?
Definition
Coulter Counter(light obscuration) and laser diffraction
Term
What are the disadvantages of volume diameter methods?
Definition
cant discriminate aggregates, expensive, training
Term
How do you calculate specific surface area of spherical particle?
Definition
SA=6/(Density*Diameter)

Density and diameter must both be in the same units cm or um
Term
What equation is gas adsorption related to?
Definition
BET

brunauer emmet equation
Term
What equation is air permeability(inertial impaction) related to?
Definition
Kozeny-Carman Equation
Term
What are the 4 general powder properties?
Definition
surface area
porosity
density
flow properties
Term
Define porosity
Definition
Measure of the void spaces in a powder
Term
What is void fraction?
Definition
void volume/total volume
Term
What factors does porosity influence?
Definition
density
flow properties
compressibility
dissolution rate
aerodynamic properties(for inhalables)
Term
What are the four types of pores in solids?
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)
Term
Which will penetrate deepest pores better: gases or liquids?
Definition
gases
Term
What are the four expressions of density?
Definition
-True density
-Granule density
-Bulk density
-Tapped Density
Term
What is true density?
Definition
density of material without pores or inter-particulate spaces

measured with pycnometer based on archimides principle
Term
What is Granule density?
Definition
Density of material with pores considered >10um
Term
What is bulk density?
Definition
Density derived from the volume occupied by an UNPACKED mass of powder
Term
What is tapped density?
Definition
Density derived from the volume occupied by a PACKED mass of powder
Term
Which densities are the most accurate?

*Density becomes greater with accuracy
Definition
1)True Density(greater than any surface density)
2)Tapped Density
3)Bulk Density
Term
What is Archimedes' principle?
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)
Term
How do you calculate true density?
Definition
p=m/(m+v-m')

m-mass of solid
v-volume of pycnometer
m'-mass of pycnometer with water+solid
Term
How do you calculate bulk density (apparent density)?
Definition
mass/volume taken up by the particles and air

measured in height but gives volume
Term
How do you calculate porosity(ϵ)?
Definition
ϵ=1-(bulk density/true density)
Term
What are the number of taps recommended when performing tapped density?
Definition
50-400
Term
What are the flow properties of powder influenced by?
Definition
-size and distribution
-shape
-porosity
-density
-surface texture
Term
What does cohesive mean?
Definition
stagnant

not free flowing
Term
What are the six problems in manufacturing dealing with flow properties of solids?
Definition
arching, rat-holing, hang up, flooding, segregation, difficulty getting level measurement
Term
What are the four inter particulate forces in powders?
Definition
Capillary Forces(moisture)
Van der Waals Forces
Mechanical interlocking
Electrostatic Charge
Term
What are the relative magnitudes of the interparticulate forces?
Definition
van der waals (smallest)
Capillary forces
adhesive binding and solid bridging(largest)
Term
What is Carr's compressibility index used for?
Definition
Measure powder flow

relationship of bulk and tapped densities
Term
How do you calculate CCI?
Definition
CCI=(Pt-P')/Pt *100%

No units
Term
Whats a good CCI?
Definition
<30% (NOT SURE)
Term
What are the relative angle of reposes for cohesive and free flowing?
Definition
Cohesive=larger angle of repose(steeper)

Free flowing= Smaller
Term
What are the ways to regulate powder flow of fine powders?
Definition
granulation(make larger?)
formulate into particles
absorb into larger particles

MAKE LARGER
Term
What are the ways to regulate powder flow of large(granule) powders?
Definition
add fines
add glidants(starch, talc, Mg stearate)
Term
What method would you use to determine particle size for injectable solution?
Definition
light scattering

electron microscope(scanning and transmission)
Term
What method would you use to determine particle size for dry powder inhaler?
Definition
laser diffraction

scanning e microscope
Term
What method would you use to determine particle size for granules for reconstitution?
Definition
optical microscope

sieving
Term
What method would you use to determine particle size for powders to fill capsules?
Definition
optical microscope

sieving
Term
What method would you use to determine particle size for tablet excipients?
Definition
sieving
Term
What would cause particles to not flocculate properly?
Definition
too large

reduce particle size
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