Lecture 2: Powders and Granules

Question 1

Powder

Answer 1

-physical form of solid material composed of particles
-dosage form for internal or external use

Question 2

Powder dosage forms

Answer 2

-oral
-topical
-inhalation

Question 3

physiochemical properties of powders

Answer 3

-particle size
-shape
-density
-solid-state properties

Question 4

Particle size affects

Answer 4

-“processability” (flow, mixing, tableting)
-formulation performance (content uniformity, dissolution)

Question 5

Particle size affects

Answer 5

-dissolution
-suspendability of suspensions
-uniformity of mixture in liquids or powders
-particles aerosol behavior for inhalation
-segregation may occur if powders have wide size distributions

Question 6

Particle size measurements

Answer 6

-sieving (mass based size)

Question 7

Particle size distribution

Answer 7

-D10: 10% of particles are smaller
-D50: 50% are smaller
-D90: 90% are smaller
-span= (D90-D10)/D50

Question 8

Width of size distribution

Answer 8

span= (D90-D10)/D50

Question 9

Mircoscopy

Answer 9

physical size?

Question 10

Projected area diameter

Answer 10

-equivalent diameter corresponding to diameter of a circle with same projected area as the irregularly shaped particle

Question 11

Laser diffraction

Answer 11

-volume based size

Question 12

Particle density

Answer 12

-true density = mass/true volume
-bulk density = mass/bulk volume

-cohesive vs non cohesive

Question 13

Powder flowability

Answer 13

-how easy powder moves to another location
-important for material conveying, transportation, and capsule and tablet die filling

Question 14

flowability of smaller particles

Answer 14

poor

Question 15

flowability of spherical particles

Answer 15

-better than needle and plate shaped particles

Question 16

milled particles

Answer 16

-cohesive (sticky)
-poor flowability

Question 17

Measurements of powder flowability

Answer 17

-angle of repose
-Carr index

Question 18

Angle of repose

Answer 18

-tanx = 2h/D
-30 degrees = great flow
>60 degrees = poor

Question 19

Carr index

Answer 19

=(tapped density- poured density)/ tapped density
-5-15%= great flow
->40%= poor

Question 20

Cohesive vs noncohesive

Answer 20

-cohesive sticks to side of tubes and to self
-noncohesive settles at the bottom of the tube

Question 21

Powder comminution

Answer 21

-particle size reduction
-improve dissolution, absorption, and mixing homogeneity
-effects of size reduction depend on design of equipment, energy, and sheat inputs of properties of the material

Question 22

Powder comminution methods (mechanical milling)

Answer 22

-ball
-hammer
-jet

Question 23

Ball mill

Answer 23

-materials + grinding medium in rotating mill

Question 24

Hammer mill

Answer 24

idk

Question 25

Jet mill

Answer 25

-generate fine particles down to 1 um -used for inhalation powders -compressed grinding air + powder

Question 26

Powder mixing (blending)

Answer 26

-unit operation involving manipulation of heterogenous physical system with the goal of making it homogenous

Question 27

Types of mixtures

Answer 27

-unmixed -ideal -random -segregation

Question 28

Major types of blending

Answer 28

-tumble blender (V-blender, tote blender, turbula blender) -blade blender (high shear blender)

Question 29

Granules

Answer 29

-dry aggregates of particles -can be used as dosage form -mostly for making tablets and capsules -improve powder flowability, reduce dusts, enhance compactibility

Question 30

Wet granulation process

Answer 30

1. blending 2. adding binder 3. granulation 4. Drying 5. Sieving

Question 31

Dry granulation process

Answer 31

1. blending 2. compression 3. Size reduction

Question 32

wet granulation

Answer 32

-high shear granulation

Question 33

Dry granulation

Answer 33

-no liquid -less processing steps and fewer risks than wet granulation -lose some compactibility for tableting

Question 34

Roller compaction

Answer 34

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