tablet PR_9

Question 1

what are tablets

Answer 1

compressed solid preparation with a single dose of one or more active medicaments

Question 2

shape of tablets

Answer 2

usually circular in shape with flat beveled or biconvex faces

Question 3

properties of oral compressed tablets

Answer 3

• intended for swallowing
• usually disintegrate in stomach
• some, with specialised function (eg. enteric-coated, modified release, effervescent, sublingual, lozenges)

Question 4

effervescent tablets

Answer 4

• rapid disintegration in water, achieved by liberation of carbon dioxide
• formulation include: alklai metal carbonates or bicarbs and organic acids (tartaric acid, citric acid)
• prepared by wet or heat fusion technique

Question 5

describe wet and heat fusion techniques

Answer 5

heat fusion: powders blend dry, with citric monohydrate used; apply heat, water of crystalisation liberated, aids granulation

wet fusion: citric acid moistened, add to sodium carbonate, granulate (cirtric acid fuse powders)

Question 6

properties of tablets

Answer 6

• have exact dosage of active principle
• confer maximum mechanical properties
• contain only inert additives/excipients
• aesthetically pleasing
• suitable for its intended purpose

Question 7

advantage of tablets

Answer 7

• convenient means of administering
• delivery an accurate dose
• small and compact
• stable product
• easy to handle and pack
• high production throughput possible

Question 8

disadvantage of tablets

Answer 8

• poor compressibility
• poor wetting
• slow dissolution
• high dose
• bitter taste/ bad odour
• sensitive to moisture

Question 9

requirement of tablets

Answer 9

1. low dose drug (filler)
2. strength (binder)
3. bioavailability (disintegrant, wetting agent)
4. tabletability (lubricant)
5. identity (colorant)

Question 10

Major types of excipients

Answer 10

• diluent/filler
• binder/ adhesive
• disintegrant
• lubricant

Question 11

minor types of excipients

Answer 11

• absorbent
• stabiliser
• wetting agent
• colorant

Question 12

excipients that affect compaction properties

Answer 12

• diluents/ fillers
• binders/ adhersives
• lubricants, glidants, anti-adherents

Question 13

excipients that affect bioavailability, stability and marketing considerations

Answer 13

• lubricants
• disintergrants
• colors, flavours, sweeteners

Question 14

diluents/fillers

Answer 14

• sugars: lactose (hydrate anhydrous), sucrose based
• starches: corn starch, pregelatinised
• celluloses: microcrystalline cellulose (large variety)
• inorganic salts: Dicalcium phsophate

mainly: inert, inexpensive, good flow, good compactability

Question 15

binders/adhesives

Answer 15

1. cellulose: microcrystalline cellulose (high strength, low friability, self lubricant, dry binder)
2. modified cellulose: methylcellulose, hydroxypropylmethylcellulose, hydroxypropylcellulose, sodium carboxymethylcellulose
3. synthetic polymers: polyvinylpyrrolidone,PVP/vinyl acetate
4. gums: sodium alginate, acacia, gelatin

Question 16

types of disintegrant

Answer 16

• starch
• microcystalline cellulose
• sodium starch glycolate
• modified cellulose gum
• cross linked polyvinypyrrolidone

Question 17

mechanism of disintegrant action

Answer 17

1. swelling (starch)
2. wicking - cap action (microcrystalline cellulose)
3. strain recovery (crospovidone)
4. interruption of particle-particle bonds (microcrystalline cellulose)
5. heat of interaction

Question 18

colorant

Answer 18

• added to provide color to tablet
• often added wet with granulation liquid
• may be added dry (need more dye)

Question 19

types of colorant

Answer 19

1. dyes (soluble or insoluble pigment types)

2. lakes (contain soluble dye deposited onto carrier particles, usually metallic salts

Question 20

lubricants

Answer 20

1. glidants: improve flow properties of granules/ powders by reducing friction between particles (ball bearing effect)
2. lubricants: reduce friction between granulation and die-wall during compaction

Question 21

examples of glidants

Answer 21

• silicates
• fused silica
• starch
• talc
• mg stearate, carbonate, oxide
• Ca/ Zn stearate

Question 22

types of lubricants

Answer 22

1. hydrodynamic (fluid type): mineral oil/ paraffin
2. boundary (solid type):
   - water insoluble: Mg/Ca stearate, stearic acid, hydrogenated veg oil (steotex), waxes
   - water soluble: carbowax (PEG), Na benzoate/acetate/lauryl sulphate, leucine

Question 23

Anti-adherents

Answer 23

• silicates and derivatives
• starch
• talc
• Mg, Ca, Zn stearates
• leucine
• sodium lauryl sulphate

Question 24

tableting machines

Answer 24

1. single punch (single station) tablet machine

2. rotary (multiple station) tablet machine

Question 25

stress of compaction forces

Answer 25

the applied force to produce a deformation

Question 26

deformation

Answer 26

change in the relative positions of different parts of the body, expressed as strain which is a change in length per unit length or volume per unit volume

Question 27

compaction cycle (compression over time)

Answer 27

``` loading 1. repacking 2. elastic deformation 3. plastic deformation 4. brittle fracture 5. visco-elastic deformation unloading 6. elastic recovery 7. plastic recovery ejection 8 visco-elastic recovery ```

Question 28

tabletability

Answer 28

capacity of powdered material to be made into a tablet of specified strength under the effect of compression pressure

Question 29

compressibility

Answer 29

ability of material to undergo volume reduction when subjected to an applied pressure

Question 30

compactibility

Answer 30

Ability of material to produce tablets with sufficient strength under the effect of densification

Question 31

mechanical strength of tablets depends on

Answer 31

1. particle size, distribution, shape 2. granule porosity 3. moisture content 4. fragmentation and visco elastic deformation 5. applied load (copaction force) 6. time of loading (strain rate sensitivity) 7. time of unloading (strain rate sensitivity) 8. elastic stress release uppon ejection

Question 32

material requirement for tabletting

Answer 32

- ideal brittle- plastic balance for good compressibility - adequate granule porosity for compressibility - sufficient moisture content for correct compressibility - good powder flow for ideal tabletability - correct level of lubrication for good compatibility

Question 33

causes of capping

Answer 33

- air entrapment - mechanism of volume reduction - compression speed - viscoelastic recovery - stress density distribution - internal shear stress

Question 34

remedies for capping

Answer 34

- lower compression forces - reduce compression speed - decrease ejection path in the die - tool design change - extend dwell time

Question 35

dfference in plastic and brittle material

Answer 35

plastic: under compressive forces will deform irreversibly brittle: under compressie forces will deform by breaking down into small fragments

Question 36

why continuous manufacturing

Answer 36

1. cost efficient 2. efficient and robust process development 3. improved product quality 4. flexible 5. reduced environmental impact

Question 37

how does CM work?

Answer 37

1. powder feed 2. blending granulation 3. drying 4. milling external phase lubricant 5. compression 6. coating