Tabletting and associated technologies Flashcards
What % of drugs are oral?
77%
What % of drugs are topical?
3%
What % of drugs are nasal/pulmonary?
1%
Pill manufacture patent?
1843 – first patent for manufacturing tablets using hand operated devices was granted (William Brockendon)
Patent was for shaping pills, lozenges and black lead by pressure
Adv of tablets?
- Improves patient compliance
- Convenient and safe way of administration
- Easy to carry multiple doses
- Accurate and reproducible doses
- Aesthetically pleasing
- Easy to store and dispense
- Solid dosage forms have better chemical and physical stability
- Ease of low cost mass production
- Possible to modify release and performance characteristics
- Possible to mask unpleasant taste and appearance
- Different tablet forms available
Disadv of tablets?
- Manufacture requires a series of unit processes + product loss at each stage
- Drug absorption dependent on gastric emptying rate = inter-patient variation
- Compression difficulties due to powder physical properties
- Administration of tablets to certain patients may be a problem e.g. Children, geriatrics, comatose, patients who have a psychological block
Excipient definition?
“An inert substance that is used as a diluent or vehicle for preparing a drug product”
What makes a tablet low dose?
Low dose tablets – active < 5% tablet weight
What makes a tablet high dose?
High dose tablets – active > 50% tablet weight
Tablet size should be proportional to the amount of drug in the formulation. True or false?
True
What is the minimum and maximum tablet weight?
< 800 mg max
50mg min
What is the max number of tablets for patient compliance?
For patient compliance ≤ 2 tablets
At what does does a tablet require a filler?
Low dose < 5 mg - purely for ease of manufacture and handling.
Concentration range for disintergrants?
Concentration range 1% – 10% w/w
e.g. starch, calcium carbonate
Binder definiton?
Binder (= adhesive) added to ensure that tablets can be formed with the required mechanical strength
Binder can be added as:
- Dry powder (for wet or dry mixing)
- Solution
Concentration range for binder:
2% to 10% w/w
What is a glidant?
to improve flowability of the powder
Either for direct compaction or for granulation
Examples of glidants and their conc range?
Talc (1 – 2% w/w), colloidal silica (0.2% w/w), magnesium stearate (1 – 5% w/w)
What is a lubricant used for?
Role: to ensure that tablet formation and ejection can occur with low friction between the tablet and the die
Concentration range for lubricant:
Concentration range 0.25 – 1% w/w
What is an anti adherent and what is its concentration range?
- Role: to reduce the adhesion between the powder and the punches
- Could lead to uneven tablet surface
- Concentration ~ 0.5% w/w
Examples:
Magnesium stearate, talc, starch
Unit process steps in manufacturing?
- Weighing
- Mixing
- Granulation
- Tabletting
- QA check
- Dissolution
- Coating
- QC check
How is a tablet formed?
The Tablet press- basic process
1) Fill the stationary hopper
2) Die filling
3) Tablet compression
4) Tablet ejection
What does weighing involve?
- Required amount of excipients
- Weight of each ingredient dependent on final weight of the tablet
Mixing process in manufacturing process:
Critical step
Homogeneity
-Uneven API content
-Uneven properties
-Affects tablet shape and size
Y-Cone blender
- Dry blending
- Wet granulation
Tablet quality assurance check involves tests to ensure quality. These include–>
- Uniformity of content
- Tablet weight
- Disintegration
- Dissolution
- Mechanical Strength
- ->Friability
- -> Fracture resistance
- Tablet appearance
Importance of powder flow?
Determination of flow properties is critical
- Affects the way the powder flows
- From hopper to die cavity
- Bulk storage containers into feed mechanisms
Uneven powder flow
- Results in air trapped in the powder
- Capping and lamination
- Excess fine powder
- Dust contamination risk to handlers
Particle interactions affecting powder flow?
Particles can stick to themselves or to surfaces
Adhesive force –>
- Between particles and container surface
- Adhesive Force α 1/particle size
- Particle size > 250 μm – free flowing.
Cohesive force –>
- Between particles
- Cohesive force α particle surface area
- Particle size < 100 μm will experience greater cohesion. Need a glidant OR to use granulation to increase particle size
Reasons for Cohesion and Adhesion? (bulk solid parameters)
Bulk Solid Parameters:
- Particle size, shape, texture and distribution
- Particle hardness and Surface characteristics
- Moisture content
- Particle density/bulk density
- Temperature
