Oral Tablets Flashcards
Is oral route the most common route?
YES
What is the European Pharmacopoeia?
A single reference work for quantity control of medicines
What is the BP?
Provides collection of authoritative official standards for UK pharmaceutical substances + medicinal products
What are the advantages of tablets?
Convenient to take + handle Better stability compared to liquid Longer shelf life precise dosing of drug Cheap to mass produce
What are the disadvantages of tablets?
Slower onset of action Poorer bioavailability = unfavourable drug properties Instability in GI Difficult to reverse therapy GI irritation
Describe disintegrating tablet
Most common
Swallowed
Release drug quickly
Excipients used are not intended to modify drug release
Why is it good that disintegrating drugs release quickly?
Aids fast + complete drug release once in digestive fluids
Why are there uncoated disintegrating tablets?
Conventional or plain tablets
Why are there coated disintegrating tablets?
Smooth surface + coloured
BUT doesn’t alter release profile
Describe gastro-resistant tablets
Delayed-release
Intended to resist gastric fluid
Release drug in intestinal fluid
What are gastro-resistant tablets covered in?
Gastro-resistant coating
OR
Granules/particles already covered with gastro-resistant coating
Describe modified-release tablets
Coated or uncoated
Contain special excipients
Should be swallowed whole
What are modified-release tablets designed for?
Modify rate, place or time at which drugs are released
What is prolonged-release?
Drug released slowly at constant rate
What is delayed-release?
Drug released at some time after adminstration
What is pulsatile-release?
Drug released from formulation in 2 or more pulses
Describe effervescent tablets
Uncoated
Intended to be dissolved/dispersed in H2O
Contain WA + carbonate/bicarbonate
Why does effervescent tablets have a high carbonate content?
Buffer solution temporarily increases stomach pH = fast emptying of stomach = drug enters intestine quicker = faster absorption = minimises stomach irritation
Why does effervescent tablets contain WA + carbonate?
React rapidly in H2O
= releases CO2
Describe sublingual tablets
Under the tongue
Describe buccal tablets
Buccal cavity (side of cheek)
What do both sublingual + buccal tablets do?
Provide rapid drug release for systemic effect without first-pass liver metabolism
Describe lozenges + pastilles
Solid, single dose preparations
Dissolve/disintegrate slowly in mouth
Local effect = oral cavity + throat
What is the difference between lozenges + pastilles?
Lozenges = hard Pastilles = soft, flexible
What are the product quality attributes
Correct dose Consistent weight, size, appearance + elegant Drug released in controlled manner Biocompatible Sufficient mechanical strength Stable throughout shelf-life Packaged safely Formulated suitable for patient
What is biocompatibility?
Not cause patient harm
Why must the product have sufficient mechanical strength?
Withstand fracture + erosion during handling
What is the most common manufacturing?
Powder compression
Describe powder compression
Requires 2 punches + die
When forced applied bonds formed
What is die filling?
1
Powder flows down from hopper into die
What is tablet formation?
2
Upper punch comes down into die
Compresses powder into tablet
When required amplified force reached
Upper punch moves upwards
What is tablet ejection?
3
Lower punch rises to eject tablet
Pushing device removes tablet form die
Describe single punch press
1 die + 1 pair of punches
Lower punch = stationary
Pressure applied by upper punch when descends
When is single punch press used?
Used in formulation development + production for clinical trials
Describe rotary press
Large scale production
Multiple punches + dies
Die table + punches rotate together
Describe tablet tooling
Come in different shapes + sizes
Dictated by different tools + design of die + punches
What are the different tablet shapes?
Circular, oval, oblong, triangular + quadratic
What are different side views?
Flat, convex
With/without bevelled edges
Why do tablets have break marks?
Facilitate tablets breaking for reproducible doses
What are different markings?
Embossed or debossed
Why do tablets have excipients?
Control quality attributes
Aid manufacturing
When would a tablet have no excipients?
If active ingredient has optimal properties
What are the excipients?
Filler (diluent) Disintegrate Binder (adhesive) Glidant Lubricant Anti-adherent
When is filler added?
When tablets more than 50mg
Why is filler added?
To increase bulk vol of powder
= increases tablet size
What is the most common filler and why is it used?
Lactose Readily dissolves in H2O Pleasant taste Good compatibility Non-hygroscopic
What is limitation of lactose?
Lactose intolerant
Why is disintegrate used?
Allows tablet to break up into small fragments when in contact with liquid
= promotes rapid drug dissolution = bioavailability
What is the most common disintegrate + why is it used?
Starch
Swells in contact with H2O
Swelling disrupts tablet = larger SA during dissolution
How much starch is normally added?
Up to 10%
Why is binder added?
Ensures granules + tablets can be formed with required mechanical strength
How can binders be added?
Powders or solutions
What are examples of solution binders?
Starch, sucrose, gelatin + polymers (PVP)
What are examples of dry binders?
Microcrystalline cellulose
Why are glidant added?
Improve powder flowability by reducing cohesion between particles
What is the most common glidant + why is it used?
Colloidal silica
Vey small particles
Adhere to particles surface of other ingredients
Reduce inter-particulate friction = improves flow
How much colloidal silica normally added?
1-2% w/w
Why is lubricant added?
Lower friction between solid + machine wall
Improve tablet formation + ejection
What is the most common lubricant?
Magnesium stearate
Why is anti-adherent added?
Reduces adhesion between powder + punch faces
Prevents particles sticking to punches
Important if tablet has markings
What are examples of anti-adherent?
Mg stearate, talc, starch + cellulose
