Micromeritics

Question 1

The science and technology of small particles

Answer 1

Micromeritics

Question 2

• Related to;
  (a) physical,
  (b) chemical, and
  (c) pharmacologic properties of a drug

Answer 2

particle size

Question 3

what does micromeritics mainly affect in dosage forms?

Answer 3

drug release

Question 4

• For non-spherical/ asymmetrical particles
• Approximate particle size based on
  diameter of sphere

Answer 4

Equivalent Spherical Diameter

Question 5

Collection of particles of uniform size

Answer 5

monodisperse

Question 6

Collection of particles of more than one size

Answer 6

polydisperse

Question 7

Represents the number of particles in each size present in a given sample

Answer 7

Particle Size Distribution

Question 8

methods of determining particle size distribution?

Answer 8

1.) number of particles
2.) weight of particles
3.) light scattering by particles
4.) volume of particles

Question 9

Optical microscopy, electron microscopy

Answer 9

number of particles

Question 10

sieving, sedimentation, centrifugation

Answer 10

weight of particles

Question 11

photon correlation spectroscopy

Answer 11

light scattering particles

Question 12

coulter counter method

Answer 12

volume of particles

Question 13

1. Sieves are arranged in a nest of about 5 with the coarsest on the top.
2. Weighed sample is placed on top sieve.
3. Sieves are shaken (mechanical shaker).
4. Powder retained on each sieve is weighed.

Answer 13

sieving technique

Question 14

up to what fineness can the sieving technique screen?

Answer 14

5 um up to 1000 um

Question 15

factors affecting analysis by sieving

Answer 15

1. Sieve loading
2. Duration of agitation
3. Intensity of agitation

Question 16

advantages of sieving

Answer 16

1. inexpensive
2. Simple
3. Rapid

Question 17

(disadvantage) what is the appreciable amount of sample needed?

Answer 17

25 g

Question 18

(disadvantages) up to what measure of particle size is difficult?

Answer 18

50 um

Question 19

(disadvantages) attrition of particles during sieving may lead to…

Answer 19

size reduction

Question 20

formula of 𝑾𝒆𝒊𝒈𝒉𝒕𝒓𝒆𝒕𝒂𝒊𝒏𝒆𝒅𝒑𝒐𝒘𝒅𝒆𝒓

Answer 20

𝑾𝒆𝒊𝒈𝒉𝒕𝒔𝒊𝒆𝒗𝒆+𝒑𝒐𝒘𝒅𝒆𝒓 −𝑾𝒆𝒊𝒈𝒉𝒕𝒔𝒊𝒆𝒗𝒆

Question 21

formula for %𝑹𝒆𝒕𝒂𝒊𝒏𝒆𝒅

Answer 21

(𝑾𝒆𝒊𝒈𝒉𝒕𝒓𝒆𝒕𝒂𝒊𝒏𝒆𝒅𝒑𝒐𝒘𝒅𝒆𝒓 / 𝑻𝒐𝒕𝒂𝒍𝑾𝒆𝒊𝒈𝒉𝒕𝒑𝒐𝒘𝒅𝒆𝒓) 𝒙 𝟏𝟎𝟎

Question 22

formula for 𝑨𝒗𝒆𝒓𝒂𝒈𝒆𝑫𝒊𝒂𝒎𝒆𝒕𝒆𝒓 𝝁𝒎

Answer 22

(Σ(%𝒓𝒆𝒕𝒂𝒊𝒏𝒆𝒅𝒙 𝒐𝒑𝒆𝒏𝒊𝒏𝒈)) / 𝟏𝟎𝟎

Question 23

1. A dilute suspension of the powder particles is prepared.
2. A drop of the suspension is mounted on a fresh slide and observed through calibrated ocular micrometer.

Answer 23

optical microscopy

Question 24

(advantage of optical microscopy) up to what can optical microscopy measure?

Answer 24

up to 1 um

Question 25

(disadvantage of optical microscopy) what is the speed of optical microscopy?

Answer 25

tedious and slow

Question 26

(disadvantage of optical microscopy) how many particles must be counted?

Answer 26

300 - 500 particles

Question 27

(disadvantage of optical microscopy) what is the measured diameter of optical microscopy?

Answer 27

2D

Question 28

powders may be...

Answer 28

(a) free-flowing (b) cohesive/sticky

Question 29

(Factors that affect flow properties) particles lead to better flow when

Answer 29

larger

Question 30

(Factors that affect flow properties) particle shape leads to better flow when

Answer 30

spherical

Question 31

(Factors that affect flow properties) this porosity leads to better flow when

Answer 31

lower

Question 32

(Factors that affect flow properties) this density leads to better flow when

Answer 32

higher

Question 33

(Factors that affect flow properties) this type of surface texture leads to better flow

Answer 33

smoother

Question 34

The maximum angle possible between the surface of a pile of powder and the horizontal plane.

Answer 34

Angle or repose (𝜭)

Question 35

formula for angle of repose

Answer 35

𝜭 = 𝒕𝒂𝒏^−𝟏 (𝒉/𝒓)

Question 36

(angle of repose) < 30

Answer 36

excellent (very free)

Question 37

(angle of repose) 31 - 35

Answer 37

good

Question 38

(angle of repose) 36 - 40

Answer 38

fair - aid not needed

Question 39

(angle of repose) 41 - 45

Answer 39

passable - may hang up

Question 40

(angle of repose) 46 - 55

Answer 40

poor - must agitate, vibrate

Question 41

(angle of repose) 56 - 65

Answer 41

very poor

Question 42

> 66

Answer 42

very, very poor

Question 43

A talc powder sample was allowed to flow onto a flat surface, a pile or heap of powder is formed with a height of 4.00 cm and base width of 6.50 cm. Calculate its angle of repose.

Answer 43

50.91𝒐

Question 44

VOLUME of material without VOIDS (intra-and inter-)

Answer 44

true volume

Question 45

VOLUME of material with intraparticular voids

Answer 45

granular volume

Question 46

VOLUME of material with VOIDS (intra-and inter-)

Answer 46

bulk volume

Question 47

formula for void volume

Answer 47

void volume = bulk volume - true volume

Question 48

density of material itself EXclusive of inter- and intraparticular voids

Answer 48

true density

Question 49

density of material itself including intraparticular voids

Answer 49

granular density

Question 50

density of material itself INclusive of inter- and intraparticular voids

Answer 50

bulk density

Question 51

Obtained after compaction by tapping or vibration

Answer 51

tapped density

Question 52

another name for tapped density

Answer 52

compressed bulk density

Question 53

Mechanical tapping is achieved by raising the cylinder and allowing it to drop under its own weight

Answer 53

determination of tapped density

Question 54

method I in determination of bulk density

Answer 54

graduated cylinder method

Question 55

formula for tapped density?

Answer 55

𝝆𝒕𝒂𝒑𝒑𝒆𝒅 = 𝒈𝒔𝒂𝒎𝒑𝒍𝒆 / 𝒎𝑳𝒕𝒂𝒑𝒑𝒆𝒅

Question 56

method II in determination of bulk density?

Answer 56

scott volumeter

Question 57

Carr reported that the more a material is compacted in a compaction or tap bulk density test, the poorer are its flow properties.

Answer 57

compressibility (carr's) index

Question 58

formula for compressibility (carr's) index?

Answer 58

𝑪.𝑰.= (𝝆𝒕𝒂𝒑𝒑𝒆𝒅 −𝝆𝒃𝒖𝒍𝒌 / 𝝆𝒕𝒂𝒑𝒑𝒆𝒅) 𝒙 𝟏𝟎𝟎

Question 59

(scale of flowability) < 10

Answer 59

excellent

Question 60

(scale of flowability) 11 - 15

Answer 60

good

Question 61

(scale of flowability) 16 - 20

Answer 61

fair

Question 62

(scale of flowability) 21 - 25

Answer 62

passable

Question 63

(scale of flowability) 26 - 31

Answer 63

poor

Question 64

(scale of flowability) 32 - 37

Answer 64

very poor

Question 65

(scale of flowability) > 38

Answer 65

very, very poor

Question 66

A measure of the air spaces or voids in a material

Answer 66

porosity

Question 67

unit of measurement for porosity

Answer 67

(𝜺) →”𝒆𝒑𝒔𝒊𝒍𝒐𝒏”

Question 68

formula for porosity (𝜺)

Answer 68

(𝜺) = (𝟏−(𝝆𝒃𝒖𝒍𝒌 / 𝝆𝒕𝒓𝒖𝒆)) 𝒙 𝟏𝟎𝟎

Question 69

(sample) starch

Answer 69

1.50

Question 70

(sample) citric acid

Answer 70

1.54

Question 71

(sample) talc

Answer 71

2.70

Question 72

(sample) activated carbon

Answer 72

2.05