Lecture 7- Tableting II

Question 1

Granulation

Answer 1

-the process in which primary powder practicals are made to form larger multi particle entities= granules

Rationale for granulation:
- prevent segregation of the constituents of powder mix
- improve the flow properties of the mix + compaction characteristics of the mix
- reduce the dust that may arise when handling powders
-hydrophobic surfaces are made hydrophilic = hydrophilic binder

Question 2

Manufacture of granulation

Answer 2

Slide 6

Question 3

Wet granulation: binders

Answer 3

Sugars/ natural binders;
-sucrose, liquid glucose, acacia, gelatin, starch, aligning acid + cellulose

Semi/synthetic polymers;
-methyl cellulose, ethyl cellulose, hydroxypropylmethyl cellulose, hydroxypropyl cellulose etc

Question 4

Granule formation

Answer 4

Nucleation —> transition —> ball growth
Slide 7

Question 5

Disadvantages of wet granulation

Answer 5

Quality: affects disintegration time
Cost: more expensive because of labour, time, equipment + energy
Loss of material: during various stages of processing
Stability: major concern for water-sensitive/ thermo-labile drugs
Multiple processing steps: adds complexity + make validation + control difficult
Incompatibilities: between formulation components

Question 6

High shear mixer granulation

Answer 6

*blending and wet massing = impeller + chopper

Advantages;
-short processing time, mixing; 2 min, granulation; 8 min, discharge; 1 min, less liquid binder is required compared to fluid bed granulation + high cohesive material can be granulated

Question 7

Fluid bed granulation

Answer 7

*granules are produced in a single step by spraying a binder solution onto a fluidized powder bed

Advantages;
-single step process (saves on everything), homogenous particles, 2-6x greater heat transfer, uniform drying + free flowing powders

Disadvantages;
-expensive, filter clogging, generation of static electricity charges + solvent explosion

Question 8

Extrusion spheronization

Answer 8

*wet mass containing drug, diluents + binder= fed to an extruder to obtain rod shaped segments
- segments are placed in the marumerizer= shaped into spheres

Advantages; granules with regular size + shape with lower friability= reduced amount of fines

Question 9

Spray drying granulation

Answer 9

*converts liquids into dry powders in a single step

Advantages;
-rapid process
-operated continuously
-suitable for heat sensitive products
-spherical particles

Question 10

Consequences of solute migration

Answer 10

• loss of active ingredient
• mottling of coloured tablets
• intragranular migration of colour

Question 11

Dry granulation

Answer 11

*uses mechanical compression by means of= slugging or roller compaction

-slugs= congested to granules by gentle milling
-roller compaction= powder is compacted between two counter rotating rolls to a ribbon by applying force
-size reduction unit= milling ribbons to desired size

Question 12

Dry granulation

Answer 12

-used when= effective dose of drug is too high or when drug is sensitive to heat/mositure

Advantages;
-ideal for moisture + heat sensitive material + for improved disintegration

Disadvantages;
-requires a specialised heavy duty tablet press/ roller compactor
-poor colour distribution
-creates more dust= increases contamination

Question 13

Tablet manufacturing

Answer 13

Die filling —> tablet formation —> tablet ejection
Slide 21-24

Question 14

Single-punch press

Answer 14

-one die + one pair of punches
-position of lower punch determines the fill weight
-lower punch stationary= during compression
Pressure = determined by upper punch displacement