Lecture 13 (Cut off for Exam 3) Flashcards
Tablets
Unique Appearances of Tablets
- Used to identify product and reduce errors
- Size, shape, weight, hardness, thickness, labeling, scoring, coating, disintegration and/or dissolution characteristics all give tablets their unique appearances
What process do solid forms go through to become small aggregates?
Disintegration
What process do solid forms or small aggregates go through to enter solution?
Dissolution
Do drugs need to be in solution to be absorbed?
Yes.
Tablet Categories (7)
- Compressed tablets
- Multiple compressed tablets
- Buccal and sublingual tablets
- Fast-dissolving or dispersing tablets
- Coated tablets (sugar, DR, sustained action)
- Administration by other routes: vaginal
- Used to prepare solutions - effervescent, dispersing, tablet titurates
Tablet Advantages (9)
- Easy to administer
- More stable than liquids
- Convenient for patient
- Economical
- Can control release of API
- Tamper resistant
- Can adjust dose
- Easy to identify
- More accurate dose
Tablet Disadvantages (6)
- Taste and odor
- Hard to swallow
- May be mistaken as candy
- Slower onset of action than liquids (esp. solutions)
- Can’t administer to everyone
- Powder flow homogeneity and compaction
Physiochemical Properties of API in Tablets
- Compaction and flow properties
- Salt form
- Polymorphic form
- Melting point
- Purity of active
- Stability/interaction with excipients
- Particle size - affects segregation and dissolution
Diluents/Fillers
-Used to bulk up mixture
-Used with potent drugs (low doses)
-Should have good compaction properties
-Ideally good flow as well
EX: Lactose and microcrystalline cellulose
Binders
-Promote adhesion of powder particles
-Important for tablet hardness and friability
-Two ways to incorporate: dry (direct compression) and liquid state (wet granulation)
EX: Starch and PVP
Disintegrating Agents
-Promote tablet disintegration in fluids
-Ideally AFTER swallowing
-Mechanism: absorbs water and swells
-Concentration affects rate of disintegration
-Can be induced multiple ways: intragranulation (in granules), extragranulation (blended with granules), and in powder blend
EX: Starch and starch derrivatives
Lubricants
-Prevent formulation/tablet sticking to machinery
-Blending times = critical
EX: Magnesium stearate and Talc
Overblending of Lubricant
- Creates hydrophobic surfaces
- Causes weaker tablet compacts
- Causes slower dissolution
Glidants
-Improve flowability of powders
-Powder flow = critical during tableting (must flow freely to fill dye cavities during process)
-Flowability measured by angle of repose (smaller the angle, better the flow)
EX: Silica derivative (Cab-O-Sil) and Talc
Dyes
- Used to make color variants on market
- FD&C dyes = water soluble colors
- FD&C lakes = insoluble aluminum dyes
- Iron oxides
- Some colorants block light as well (opacifiers)
Flavors & Sweetners
- “Mask” taste/odor of drugs or excipients
- Spray dried and other flavors
- Natural and artificial sweetners
Machinery Used to Make Tablets
- Single Station Tablet Press - punches and dies single tablet at a time
- Mutli-Station Tablet Press - punches and dies multiple tablets at a time
What gives tablets their unique shapes and appearances?
Punches and dies. They dictate shape, size, and surface of tablet
Tablet Production Methods (4)
- Direct compression
- Wet granulation - manually or by fluid bed
- Dry Granulation (roller compaction)
- Other methods - Ink-jet printing, hot melt extrusion
Direct Compression
-Requires powders to be free-flowing and compressible
Steps:
- Size drugs with sieves
- Weigh specific amounts of API/excipients
- Blend ingredients well (add lubricants AFTERWARDS)
- Compress into tablets
Direct Compression Problems (4)
- Content uniformity in low dose drugs
- Compressibility of high-dose drugs
- Segregation in hopper is possible
- Blending of lubricant is CRITICAL