Mixing granulation final

Question 2

What is the tablet manufacturing processing chain?

Answer 2

Comminution → Mixing → (Granulation or Direct compression) → Compression → Drying/Coating → Packaging.

Question 3

What problem does each step solve?

Answer 3

Comminution: dissolution & content uniformity; Mixing: dose accuracy; Granulation: flow & segregation; Compression: mechanical strength.

Question 4

Define mixing in pharmaceutics.

Answer 4

Combining ingredients so particles of each component are positioned close to the others to achieve uniform distribution.

Question 5

What is the goal of mixing in tablet manufacture?

Answer 5

Uniform drug distribution (content uniformity).

Question 6

What tablet components must be mixed?

Answer 6

API, diluent, binder, disintegrant, lubricant, glidant.

Question 7

Why is mixing critical?

Answer 7

Ensures content uniformity, therapeutic efficacy, safety, and regulatory compliance.

Question 8

What happens if mixing is poor?

Answer 8

Dose errors, toxicity/underdosing, and failed tablets.

Question 9

How does dose affect content uniformity risk?

Answer 9

<10 mg = high risk; 10–50 mg = moderate; >50 mg = low risk.

Question 10

Why are low-dose drugs problematic?

Answer 10

Few particles lead to statistical variation and large dose errors.

Question 11

How can content uniformity be improved?

Answer 11

Micronisation, efficient mixing, ordered mixing, and granulation.

Question 12

Degrees of mixing?

Answer 12

Segregated, partial mix, random mix, ordered mix.

Question 13

Target mixture type?

Answer 13

Random or ordered mixture.

Question 14

What is an ordered mixture?

Answer 14

Small particles adhere onto larger carrier particles.

Question 15

What forces cause ordered mixing?

Answer 15

van der Waals, electrostatic attraction, cohesive forces.

Question 16

Why are ordered mixtures useful?

Answer 16

Drug particles move with carriers, improving flow and dose uniformity.

Question 17

Advantages of ordered mixtures?

Answer 17

Reduce segregation, improve flow, improve content uniformity.

Question 18

Where are ordered mixtures used?

Answer 18

Inhaler powders, potent drugs, and direct compression tablets.

Question 19

What is segregation?

Answer 19

Separation of components during handling.

Question 20

Causes of segregation?

Answer 20

Particle size, density, shape differences, and vibration/transport.

Question 21

Consequences of segregation?

Answer 21

Dose variation, weight variation, tablet failure.

Question 22

Types of mixing mechanisms?

Answer 22

Convective, diffusive, and shear mixing.

Question 23

Describe convective, diffusive, and shear mixing.

Answer 23

Convective: bulk movement; Diffusive: random motion; Shear: layers slide.

Question 24

Tumbling mixers — features and examples?

Answer 24

Rotating container, low shear, free-flowing powders; examples: double cone, twin shell, drum, IBC.

Question 25

Agitator mixers — features and examples?

Answer 25

Blades/paddles for cohesive powders; examples: ribbon and planetary mixers.

Question 26

Fluidised bed mixer — function?

Answer 26

Air suspends powder; mixing, granulation, and drying in one unit.

Question 27

What are granules?

Answer 27

Aggregates of powder particles (~200–500 µm for tablets).

Question 28

Why perform granulation?

Answer 28

Prevent segregation, improve flow, compaction, tablet strength, and reduce dust.

Question 29

Key concept of granulation?

Answer 29

Particles move together as one unit (isodiametric).

Question 30

Wet granulation steps?

Answer 30

Mix → add binder solution → wet mass → sieve → dry → resieve → add lubricant.

Question 31

How do wet granules form?

Answer 31

Binder solution dries and forms solid bridges.

Question 32

Examples of binders?

Answer 32

Starch, acacia, methylcellulose, sodium CMC.

Question 33

When is dry granulation used and methods?

Answer 33

Heat/moisture-sensitive drugs; slugging and roller compaction.

Question 34

What is melt granulation?

Answer 34

Hot-melt binder (e.g., PEG, stearic acid) solidifies on cooling; no solvent needed.

Question 35

Stages of wet granulation with increasing liquid?

Answer 35

Pendular → Funicular → Capillary → Suspension.

Question 36

Which stage produces strongest granules?

Answer 36

Capillary state.

Question 37

Mechanisms of granule bonding?

Answer 37

Liquid bridges, solid bridges, van der Waals forces, electrostatic forces, mechanical interlocking.

Question 38

Purpose of drying?

Answer 38

Remove solvent without degrading drug.

Question 39

Why latent heat matters?

Answer 39

Evaporates water rather than heating the drug.

Question 40

Types of dryers?

Answer 40

Tray dryer, fluidised bed dryer, vacuum oven, microwave dryer.

Question 41

Free moisture vs equilibrium moisture?

Answer 41

FMC: surface water, easy to remove; EMC: bound water dependent on RH, hard to remove.

Question 42

Why won’t extended drying remove EMC?

Answer 42

Requires reduction in relative humidity.

Question 43

Define relative humidity.

Answer 43

(Water vapour pressure / saturated vapour pressure at same temperature) × 100.

Question 44

How does moisture affect powders?

Answer 44

Affects granule strength, flow, and tablet hardness.

Question 45

Effect of too dry vs too wet powder?

Answer 45

Too dry causes static and poor flow; too wet causes sticking.

Question 46

Key principle of moisture in processing?

Answer 46

Powders require small residual moisture for optimal processing.

Question 47

What is direct compression and requirements?

Answer 47

Tablet formation without granulation; needs good flow and compressibility.

Question 48

Examples of direct compression excipients?

Answer 48

Spray-dried lactose, MCC, dibasic calcium phosphate.

Question 49

Advantages of direct compression?

Answer 49

Cheap, fast, fewer processing steps.

Question 50

Ordered mixtures prevent what?

Answer 50

Segregation and improve content uniformity.

Question 51

Why do low-dose drugs risk non-uniformity?

Answer 51

Few particles per tablet.

Question 52

What does granulation improve?

Answer 52

Flow and dose accuracy.

Question 53

What liquid bridge state is strongest?

Answer 53

Capillary state.

Question 54

When is dry granulation used?

Answer 54

Heat- or moisture-sensitive drugs.

Question 55

Why is EMC important?

Answer 55

Cannot be removed without lowering RH.

Question 56

Why do powders need slight moisture?

Answer 56

Prevent static and sticking; improve flow.

Question 57

Why does mixing affect tablet efficacy?

Answer 57

Determines dose accuracy and therapeutic effect.

Question 58

Why does granulation improve tablet manufacture?

Answer 58

Prevents segregation and improves compaction.

Question 59

What overall concept links this lecture to tablets?

Answer 59

Proper mixing and granulation ensure correct dose, manufacturability, and effective drug delivery.