Pharmaceutics - Tableting and Roller Compacting Flashcards
(36 cards)
what are advantages of tablets?
- Portable and convenient.
- Accurate dosing.
- Large GI surface area for drug absorption.
- Solid dosage form stable.
- Scalable for mass production.
- MR formulations.
- Excellent patient acceptability
what are the disadvantages of tablets?
- Degradation by pH or enzyme in GI tract.
- Not suitable if patient unconscious or dysphagic.
- Difficult to withdraw therapy.
- Food effects on drug absorption
what are the types of tablets based on their mode of administration?
oral
effervescent
sublingual
buccal
what are the types of tablets based on their release profile?
IR (Immediate Release) ME (Modified Release) DR (Delayed Release) ER (Extended Release) SR (Sustained Release) CR (Controlled Release)
what do all medicines typically contain?
- Drug
- Filler
- Binder
- GLidant
- Lubricant
- Anti-adherent
What other excipients do IR tablets have besides the norm in other drugs?
disintegrants and coating
What other excipients do MR tablets have besides the norm in other drugs?
coating and matrix former
what is wet granulation?
Aggregation of primary particles using binder solution.
two types: (Shear granulation, fluidised bed granulation)
what is dry granulation?
Aggregation of primary particles using solid binders.
two types: (Slugging or roller compaction followed by milling)
what is direct compression?
Compaction of primary particles on tablet press without the need of granulation. Uses dry binders and cohesive powder
Explain the dry granulation technique and give an example of one?
- dry granulation is the compaction of powders into a ribbon which is then milled into granules.
- an example is roller compaction
what are the different compartments of a roller compaction and describe their roles?
- Feeder unit: feeds powder to compaction rollers.
- Compaction unit: Pair of rollers rotating in opposite directions compact powder into ribbon.
- Size reduction unit: Mills compacted ribbon into granules.
what is a single-station tablet press?
- a device driven by an eccentric motor with a low throughput (i.e. doesn’t make many tablets).
- it compresses the powders then ejects them as tablets
what is a multi-station (rotary) tablet press?
- a tablet press driven by rolls and cams
- presses the powder on a rotating turret to form a tablet on ejection
- has a high throughput
explain the compaction cycle?
- Filling
- Compression
- Ejection
what are the types of tablet defects?
- Capping: Top of tablet separates from main body.
- Lamination: Tablet body separates into layers.
- Cracking: Capping and/or lamination.
- Mottling: Uneven surface colour distribution.
- Chipping: Material removed from edges of friable tablets.
- Sticking: Powder adheres to punches.
- Picking: Embossed detail removed from tablet surface.
what causes cracking in tablets?
-Air entrapment;
-inadequate dwell time;
-excessive die wall
friction.
what causes mottling in tablets?
- Inadequate mixing;
- solute migration.
what causes sticking of tablets?
Adhesive powder.
what is the solution to cracking?
-Pre-compression;
-tapered die;
-increase
dwell time;
-lubrication
what is the solution to mottling?
- Adequate mixing;
- avoid static bed drying;
- coating.
what is the solution to sticking?
-Anti-adherent;
-non-stick coating of punches;
-increase dwell time;
-particle size and
humidity control.
what is an osmotic system?
when the drug is forced through the orifice in the tablet coating by hydrostatic pressure
what is a gastroretentive dosage form?
one which is retained in the stomach for drug release
