MICROMERITICS

Question 1

The science and technology of small particles

Answer 1

MICROMERITICS

Question 2

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

Answer 2

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

Question 3

IMPORTANCE IN PHARMACY

Answer 3

¡ 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

Question 4

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

Answer 4

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.

Question 5

METHODS FOR DETERMINING PARTICLE
SIZE

Answer 5

¡Microscopy
¡Sieving
¡Sedimentation
¡Determination of particle volume

Question 6

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

Answer 6

Ordinary microscope; 0.2 -100 micron

Question 7

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

Answer 7

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

Question 8

3 measurements for optical microscopy:

Answer 8

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

Question 9

◼ 2 tangents separated by
the longest distance

Answer 9

a. Ferret Diameter

Question 10

◼ distance that will bisect
the particle into halves

Answer 10

b. Martin Diameter

Question 11

◼ diameter of the circle that
will enclose the particle

Answer 11

c. Projected Area of the
Circle

Question 12

a. Ferret Diameter
◼_____ separated by
the ____

Answer 12

2 tangents;longest distance

Question 13

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

Answer 13

bisect; halves

Question 14

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

Answer 14

enclose

Question 15

DISADVANTAGES OF OPTICAL MICROSCOPY

Answer 15

◼ 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.

Question 16

ADVANTAGES OF OPTICAL MICROSCOPY

Answer 16

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

Question 17

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

Answer 17

Sieving

Question 18

Sieving
◼ This method uses series of ______ calibrated by ______

Answer 18

standard sieves;National Bureau of Standards

Question 19

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

Answer 19

grading coarser particles; 44 micron (#325 sieve)

Question 20

SIEVING ERRORS ARRIVED FROM:

Answer 20

¡Sieve loading
¡Duration and intensity of
agitation

Question 21

MW
determination of high polymers

Answer 21

Ultracentrifugation:

Question 22

Ultracentrifugation: ____
determination of _____

Answer 22

MW; high polymers
`

Question 23

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

Answer 23

deflocculating agent; free; separate

Question 24

OTHER METHODS BASED ON
SEDIMENTATION:

Answer 24

Ø
Pipette method
Ø Balance method
Ø Hydrometer method

Question 25

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

Answer 25

Andreasen Apparatus

Question 26

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

Answer 26

550-mL; 10-mL; ground glass stopper

Question 27

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

Answer 27

lower tip is 20 cm

Question 28

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

Answer 28

Coulter counter

Question 29

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

Answer 29

electrodes; electric resistance

Question 30

Automatic Particle Counters:

Answer 30

¡ Coulter Counter: ¡ HIAC/Royco Instrument: ¡ Gelman Counter:

Question 31

Coulter counter principle:

Answer 31

Electric resistance

Question 32

HIAC/Royco Instrument principle:

Answer 32

Light blockage

Question 33

Gelman Counter principle:

Answer 33

Faraday-Tyndall Effect

Question 34

ADVANTAGE OF PARTICLE COUNTERS

Answer 34

¡ 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

Question 35

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.

Answer 35

living or dead cells dust and bacteria. sized particle expense

Question 36

¡ A sphere has minimum surface area _____

Answer 36

per unit volume.

Question 37

¡ The more ____, the greater the _____

Answer 37

asymmetric a particle;surface area per unit volume

Question 38

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

Answer 38

direct calculation

Question 39

METHODS FOR DETERMINING SURFACE AREA:

Answer 39

¡ 1) Adsorption Method 2. AIR PERMEABILITY METHOD

Question 40

¡ 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.

Answer 40

¡ 1) Adsorption Method

Question 41

¡ 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.

Answer 41

adsorbed; monolayer;

Question 42

theory of adsorption.

Answer 42

Brunauer-Emmett-Teller (BET)`

Question 43

¡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.

Answer 43

2. AIR PERMEABILITY METHOD

Question 44

2. 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.

Answer 44

permeates

Question 45

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

Answer 45

cracks and pores; interstices

Question 46

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

Answer 46

adsorption of moisture or air

Question 47

DERIVED PROPERTIES OF POWDERS

Answer 47

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

Question 48

¡ The ratio of the void volume to the bulk volume

Answer 48

POROSITY

Question 49

POROSITY ¡ The ratio of the _____ volume to the_____ volume

Answer 49

void; bulk

Question 50

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

Answer 50

¡ Bulk volume

Question 51

¡ This is known as the volume of spaces between particles

Answer 51

¡ Void Volume

Question 52

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

Answer 52

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

Question 53

nonporous powder:

Answer 53

(no internal pores or capillary spaces),

Question 54

______ can assume either one of two ideal packing arrangement

Answer 54

Powder beds or uniform sized spheres

Question 55

PACKING ARRANGEMENT:

Answer 55

Ø Closest or rhombohedral Ø Loosest or cubic packing

Question 56

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

Answer 56

hard and smooth rough and spongy

Question 57

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

Answer 57

True Density:

Question 58

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

Answer 58

Granule Density:

Question 59

Determined from the bulk volume

Answer 59

Bulk Density:

Question 60

Specific bulk volume, the reciprocal of bulk density is called

Answer 60

bulkiness or bulk

Question 61

Bulkiness _____ with a ____in particle size.

Answer 61

increases;decrease

Question 62

A bulk powder is somewhat analogous to a

Answer 62

non-Newtonian liquid,

Question 63

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

Answer 63

plastic flow dilatancy

Question 64

¡Accordingly, powders may be

Answer 64

free- flowing or cohesive

Question 65

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

Answer 65

glidants (Mg stearate and talc)

Question 66

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

Answer 66

ability of a powder to flow

Question 67

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

Answer 67

ØMixing, and the prevention of unmixing

Question 68

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

Answer 68

Neumann

Question 69

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 _____.

Answer 69

rigid particles closest packing tapping experiments

Question 70

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

Answer 70

dilatant

Question 71

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 ______

Answer 71

compression lower closest packing

Question 72

Volume occupied by the powder

Answer 72

BULK VOLUME

Question 73

Volume of the spaces between the particle

Answer 73

VOID VOLUME

Question 74

The ratio of the void volume to the bulk volume

Answer 74

POROSITY

Question 75

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

Answer 75

PACKING ARRANGEMENT

Question 76

Reciprocal of bulk density

Answer 76

BULK SPECIFIC VOLUME

Question 77

From the true and granule density

Answer 77

Intraparticle porosity

Question 78

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

Answer 78

Interspace/ void porosity