Physical Pharmacy Laboratory > Micromeritics > Flashcards

Micromeritics Flashcards

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1
Q

The science and technology of small particles

A

Micromeritics

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2
Q
  • Related to;
    (a) physical,
    (b) chemical, and
    (c) pharmacologic properties of a drug
A

particle size

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3
Q

what does micromeritics mainly affect in dosage forms?

A

drug release

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4
Q
  • For non-spherical/ asymmetrical particles
  • Approximate particle size based on
    diameter of sphere
A

Equivalent Spherical Diameter

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5
Q

Collection of particles of uniform size

A

monodisperse

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6
Q

Collection of particles of more than one size

A

polydisperse

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7
Q

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

A

Particle Size Distribution

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8
Q

methods of determining particle size distribution?

A

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

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9
Q

Optical microscopy, electron microscopy

A

number of particles

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10
Q

sieving, sedimentation, centrifugation

A

weight of particles

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11
Q

photon correlation spectroscopy

A

light scattering particles

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12
Q

coulter counter method

A

volume of particles

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13
Q
  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.
A

sieving technique

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14
Q

up to what fineness can the sieving technique screen?

A

5 um up to 1000 um

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15
Q

factors affecting analysis by sieving

A
  1. Sieve loading
  2. Duration of agitation
  3. Intensity of agitation
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16
Q

advantages of sieving

A
  1. inexpensive
  2. Simple
  3. Rapid
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17
Q

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

A

25 g

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18
Q

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

A

50 um

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19
Q

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

A

size reduction

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20
Q

formula of π‘Ύπ’†π’Šπ’ˆπ’‰π’•π’“π’†π’•π’‚π’Šπ’π’†π’…π’‘π’π’˜π’…π’†π’“

A

π‘Ύπ’†π’Šπ’ˆπ’‰π’•π’”π’Šπ’†π’—π’†+π’‘π’π’˜π’…π’†π’“ βˆ’π‘Ύπ’†π’Šπ’ˆπ’‰π’•π’”π’Šπ’†π’—π’†

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21
Q

formula for %π‘Ήπ’†π’•π’‚π’Šπ’π’†π’…

A

(π‘Ύπ’†π’Šπ’ˆπ’‰π’•π’“π’†π’•π’‚π’Šπ’π’†π’…π’‘π’π’˜π’…π’†π’“ / π‘»π’π’•π’‚π’π‘Ύπ’†π’Šπ’ˆπ’‰π’•π’‘π’π’˜π’…π’†π’“) 𝒙 𝟏𝟎𝟎

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22
Q

formula for π‘¨π’—π’†π’“π’‚π’ˆπ’†π‘«π’Šπ’‚π’Žπ’†π’•π’†π’“ ππ’Ž

A

(Ξ£(%π’“π’†π’•π’‚π’Šπ’π’†π’…π’™ π’π’‘π’†π’π’Šπ’π’ˆ)) / 𝟏𝟎𝟎

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23
Q
  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.
A

optical microscopy

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24
Q

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

A

up to 1 um

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25
(disadvantage of optical microscopy) what is the speed of optical microscopy?
tedious and slow
26
(disadvantage of optical microscopy) how many particles must be counted?
300 - 500 particles
27
(disadvantage of optical microscopy) what is the measured diameter of optical microscopy?
2D
28
powders may be...
(a) free-flowing (b) cohesive/sticky
29
(Factors that affect flow properties) particles lead to better flow when
larger
30
(Factors that affect flow properties) particle shape leads to better flow when
spherical
31
(Factors that affect flow properties) this porosity leads to better flow when
lower
32
(Factors that affect flow properties) this density leads to better flow when
higher
33
(Factors that affect flow properties) this type of surface texture leads to better flow
smoother
34
The maximum angle possible between the surface of a pile of powder and the horizontal plane.
Angle or repose (𝜭)
35
formula for angle of repose
𝜭 = 𝒕𝒂𝒏^βˆ’πŸ (𝒉/𝒓)
36
(angle of repose) < 30
excellent (very free)
37
(angle of repose) 31 - 35
good
38
(angle of repose) 36 - 40
fair - aid not needed
39
(angle of repose) 41 - 45
passable - may hang up
40
(angle of repose) 46 - 55
poor - must agitate, vibrate
41
(angle of repose) 56 - 65
very poor
42
> 66
very, very poor
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.
50.91𝒐
44
VOLUME of material without VOIDS (intra-and inter-)
true volume
45
VOLUME of material with intraparticular voids
granular volume
46
VOLUME of material with VOIDS (intra-and inter-)
bulk volume
47
formula for void volume
void volume = bulk volume - true volume
48
density of material itself EXclusive of inter- and intraparticular voids
true density
49
density of material itself including intraparticular voids
granular density
50
density of material itself INclusive of inter- and intraparticular voids
bulk density
51
Obtained after compaction by tapping or vibration
tapped density
52
another name for tapped density
compressed bulk density
53
Mechanical tapping is achieved by raising the cylinder and allowing it to drop under its own weight
determination of tapped density
54
method I in determination of bulk density
graduated cylinder method
55
formula for tapped density?
𝝆𝒕𝒂𝒑𝒑𝒆𝒅 = π’ˆπ’”π’‚π’Žπ’‘π’π’† / π’Žπ‘³π’•π’‚π’‘π’‘π’†π’…
56
method II in determination of bulk density?
scott volumeter
57
Carr reported that the more a material is compacted in a compaction or tap bulk density test, the poorer are its flow properties.
compressibility (carr's) index
58
formula for compressibility (carr's) index?
π‘ͺ.𝑰.= (𝝆𝒕𝒂𝒑𝒑𝒆𝒅 βˆ’π†π’ƒπ’–π’π’Œ / 𝝆𝒕𝒂𝒑𝒑𝒆𝒅) 𝒙 𝟏𝟎𝟎
59
(scale of flowability) < 10
excellent
60
(scale of flowability) 11 - 15
good
61
(scale of flowability) 16 - 20
fair
62
(scale of flowability) 21 - 25
passable
63
(scale of flowability) 26 - 31
poor
64
(scale of flowability) 32 - 37
very poor
65
(scale of flowability) > 38
very, very poor
66
A measure of the air spaces or voids in a material
porosity
67
unit of measurement for porosity
(𝜺) β†’β€π’†π’‘π’”π’Šπ’π’π’β€
68
formula for porosity (𝜺)
(𝜺) = (πŸβˆ’(π†π’ƒπ’–π’π’Œ / 𝝆𝒕𝒓𝒖𝒆)) 𝒙 𝟏𝟎𝟎
69
(sample) starch
1.50
70
(sample) citric acid
1.54
71
(sample) talc
2.70
72
(sample) activated carbon
2.05
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