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PPAR > MICROMERITICS > Flashcards

MICROMERITICS Flashcards

1
Q

The science and technology of small particles

A

MICROMERITICS

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2
Q

MICROMERITICS
The unit of particle size used most frequently is_____,also called _____, equal to 10-6 m, 10-4 cm, 10-3 mm

A

micrometer (μm);micron; 10-6 m, 10-4 cm, 10-3 mm

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3
Q

IMPORTANCE IN PHARMACY

A

¡ Particle can be related in a significant way to the
physical, chemical, and pharmacologic properties
of a drug.
¡ Release from dosage forms
¡ The successful formulation of suspensions,
emulsions, and tablets
¡ In the area of tablet and capsule manufacture

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4
Q

In a collection of particles of more than one
size, two properties are important, namely

A

the shape and surface area of the
individual particles, and
Ø the size range and number or weight of
particles present and, hence, the total
surface area.

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5
Q

METHODS FOR DETERMINING PARTICLE
SIZE

A

¡Microscopy
¡Sieving
¡Sedimentation
¡Determination of particle volume

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6
Q
  1. OPTICAL MICROSCOPY
    ¡ _______ can be used for
    particle-size measurement in the range of ____ to about ____”
A

Ordinary microscope; 0.2 -100 micron

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7
Q

OPTICAL MICROSCOPY
OPERATIONAL USE
¡Accordingly to the _______ an ____OR____,_____,____
is _____ on a slide or ruled cell
and placed on a mechanical stage.

A

Microscopic methd; emulsion or
suspension, diluted or undiluted; mounted

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8
Q

3 measurements for optical microscopy:

A

a. Ferret Diameter
b. Martin Diameter
c. Projected Area of the
Circle

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9
Q

◼ 2 tangents separated by
the longest distance

A

a. Ferret Diameter

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10
Q

◼ distance that will bisect
the particle into halves

A

b. Martin Diameter

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11
Q

◼ diameter of the circle that
will enclose the particle

A

c. Projected Area of the
Circle

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12
Q

a. Ferret Diameter
◼_____ separated by
the ____

A

2 tangents;longest distance

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13
Q

b. Martin Diameter
◼ distance that will _____
the particle into_____

A

bisect; halves

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14
Q

c. Projected Area of the
Circle
◼ diameter of the circle that
will _____ the particle

A

enclose

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15
Q

DISADVANTAGES OF OPTICAL MICROSCOPY

A

◼ Diameter is obtained from only two dimensions of the particle: length and breadth.
◼ No estimation of the depth (thickness) of the particle is ordinarily available.
◼ The number of particles that must be counted (300 to 500) to obtain a good emulsion of the distribution makes the method somewhat slow and tedious.

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16
Q

ADVANTAGES OF OPTICAL MICROSCOPY

A

◼The presence of agglomerates and particles of more than one
component may often be detected.

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17
Q

◼ This method uses series of standard sieves calibrated by National Bureau of Standards

A

Sieving

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18
Q

Sieving
◼ This method uses series of ______ calibrated by ______

A

standard sieves;National Bureau of Standards

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19
Q

◼ Sieves are generally used for ________; if extreme care is used, however, they may be employed for screening material as fine as____-

A

grading coarser particles; 44 micron (#325 sieve)

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20
Q

SIEVING ERRORS ARRIVED FROM:

A

¡Sieve loading
¡Duration and intensity of
agitation

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21
Q

MW
determination of high polymers

A

Ultracentrifugation:

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22
Q

Ultracentrifugation: ____
determination of _____

A

MW; high polymers
`

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23
Q

◼Proper _____must be found for each sample that will keep the particles _____ and_____ as they fall thru the medium.

A

deflocculating agent; free; separate

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24
Q

OTHER METHODS BASED ON
SEDIMENTATION:

A

Ø
Pipette method
Ø Balance method
Ø Hydrometer method

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25
Q

550-mL vessel containing a 10-
mL pipette sealed into a ground
glass stopper

A

Andreasen Apparatus

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26
Q

Andreasen Apparatus
_____ vessel containing a ____ pipette sealed into a _______

A

550-mL; 10-mL; ground glass stopper

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27
Q

Andreasen Apparatus
When the pipette is place in
the cylinder, its _________ below the surface of the
suspension

A

lower tip is 20
cm

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28
Q

this instrument
operates the principle that when a
particle suspended in a conducting
liquid passes thru a small orifice on
either side of which are electrodes, a change in electric resistance occurs

A

Coulter counter

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29
Q

Coulter counter
this instrument
operates the principle that when a
particle suspended in a conducting
liquid passes thru a small orifice on
either side of which are _____, a change in ________ occurs

A

electrodes; electric resistance

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30
Q

Automatic Particle Counters:

A

¡ Coulter Counter:

¡ HIAC/Royco Instrument:

¡ Gelman Counter:

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31
Q

Coulter counter principle:

A

Electric resistance

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32
Q

HIAC/Royco Instrument principle:

A

Light blockage

33
Q

Gelman Counter principle:

A

Faraday-Tyndall Effect

34
Q

ADVANTAGE OF PARTICLE COUNTERS

A

¡ For study of particle growth and
dissolution; study of the effect of
antibacterial agents on the growth
of microorganisms
¡the simplicity of its operation and
its reproducibility

35
Q

LIMITATIONS OF PARTICLE COUNTERS:
¡ As in microscopic counts, the machine cannot
distinguish between _______
even between _____
¡ Any reasonably _____ in the solution will be counted.
¡ There is also the ______ of buying the
counter, which can cost many thousands of
dollars.

A

living or dead cells
dust and bacteria.
sized particle
expense

36
Q

¡ A sphere has minimum surface area _____

A

per
unit volume.

37
Q

¡ The more ____, the
greater the _____

A

asymmetric a particle;surface area per unit volume

38
Q

METHODS FOR DETERMINING SURFACE AREA
¡ Two methods are commonly available that permit
_____ of surface area.

A

direct calculation

39
Q

METHODS FOR DETERMINING SURFACE
AREA:

A

¡ 1) Adsorption Method
2. AIR PERMEABILITY METHOD

40
Q

¡ the amount of a gas or liquid solute that is
adsorbed on the samples of powder to form a
monolayer is the direct function of the surface area
of the sample.

A

¡ 1) Adsorption Method

41
Q

¡ 1) Adsorption Method
¡ the amount of a gas or liquid solute that is
______ on the samples of powder to form a
______ is the direct function of the surface area
of the sample.

A

adsorbed; monolayer;

42
Q

theory of
adsorption.

A

Brunauer-Emmett-Teller (BET)`

43
Q

¡Depends on the fact that the rate at
which a gas or liquid permeates
a bed of powder is related, among
other factors, to the surface area
exposed to permeate.

A
  1. AIR PERMEABILITY METHOD
44
Q
  1. AIR PERMEABILITY METHOD
    ¡Depends on the fact that the rate at
    which a gas or liquid _____
    a bed of powder is related, among
    other factors, to the surface area
    exposed to permeate.
A

permeates

45
Q

Materials of high specific area may have _______&_____ that adsorb gases and vapors, such as water, into their______.

A

cracks and pores; interstices

46
Q

Relatively powdered drugs may dissolve more or less in aqueous medium depending upon their______.

A

adsorption of moisture or air

47
Q

DERIVED PROPERTIES OF POWDERS

A

¡ Porosity
¡ Packing arrangement
¡ Densities of particles
¡ Bulkiness
¡ Flow properties
¡ Compaction

48
Q

¡ The ratio of the void volume to
the bulk volume

A

POROSITY

49
Q

POROSITY
¡ The ratio of the _____ volume to the_____ volume

A

void; bulk

50
Q

¡ Example: zinc oxide placed in
graduated cylinder where the
total volume is noted.

A

¡ Bulk volume

51
Q

¡ This is known as the volume
of spaces between particles

A

¡ Void Volume

52
Q

¡In the case of nonporous powder (no
internal pores or capillary spaces),
bulk volume of the powder is equal
to:

A

Øthe true volume of the solid particles plus the volume of the spaces between
particles

53
Q

nonporous powder:

A

(no
internal pores or capillary spaces),

54
Q

______ can assume either one
of two ideal packing arrangement

A

Powder beds or uniform sized
spheres

55
Q

PACKING ARRANGEMENT:

A

Ø Closest or rhombohedral
Ø Loosest or cubic packing

56
Q

¡ Since particles may be _____ in one case, and _____ in another, one must express
densities with great care

A

hard and
smooth
rough and
spongy

57
Q

Density of the material itself,
exclusive of the voids and intra-particle pores larger
than molecular or atomic dimensions in the crystal
lattices

A

True Density:

58
Q

Determined by the displacement
of mercury which does not penetrate at ordinary
pressures into pores smaller than about 10 micron

A

Granule Density:

59
Q

Determined from the bulk volume

A

Bulk Density:

60
Q

Specific bulk volume, the reciprocal
of bulk density is called

A

bulkiness or
bulk

61
Q

Bulkiness _____ with a ____in particle size.

A

increases;decrease

62
Q

A bulk powder is somewhat
analogous to a

A

non-Newtonian liquid,

63
Q

A bulk powder is somewhat
analogous to a non-Newtonian liquid,
which exhibits _____ and
sometimes _____, the particle
being influenced by attractive forceso varying degrees

A

plastic flow

dilatancy

64
Q

¡Accordingly, powders may be

A

free-
flowing or cohesive

65
Q

To improve flow characteristics,
materials termed ____ are frequently
added to granular powders

A

glidants
(Mg stearate and talc)

66
Q

is one of the factors involving in
mixing materials to form a
powder blend.

A

ability of a powder to flow

67
Q

______, is an important
pharmaceutical operation involved in
the preparation of many dosage
forms, including tablets and capsules

A

ØMixing, and the prevention of
unmixing

68
Q

Compressed tablets: ______found that when
powders were compacted under a pressure of about 5
kg/cm2,

A

Neumann

69
Q

Compressed tablets: Neumann found that when
powders were compacted under a pressure of about 5
kg/cm2, the porosities of the powders composed
of ______ (sodium carbonate, for example)
were higher than the porosities of powders in
_____, as determined by _____.

A

rigid particles

closest packing

tapping
experiments

70
Q

Compressed tablets: Neumann found that when
powders were compacted under a pressure of about 5
kg/cm2, the porosities of the powders composed
of rigid particles (sodium carbonate, for example)
were higher than the porosities of powders in
closest packing, as determined by tapping
experiments. Hence, these powders were ______, that
is contraction, under the influence of stress

A

dilatant

71
Q

In the case of soft and spongy
particle (kaolin), however, the
particles deformed on ______,
and the porosities were _____than
other tapping the powder down to its
condition if ______

A

compression

lower

closest packing

72
Q

Volume occupied by the powder

A

BULK VOLUME

73
Q

Volume of the spaces between the particle

A

VOID VOLUME

74
Q

The ratio of the void volume to the bulk volume

A

POROSITY

75
Q

Powder beds or uniform sized spheres can assume either one of
two ideal packing arrangement
Ø Closest or rhombohedral
Ø Loosest or cubic packing

A

PACKING
ARRANGEMENT

76
Q

Reciprocal of bulk density

A

BULK SPECIFIC
VOLUME

77
Q

From the true and granule density

A

Intraparticle porosity

78
Q

Relative volume of interspace voids to the bulk volume of the
powder.

A

Interspace/ void
porosity

PPAR (13 decks)

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