PSII Exam III Flashcards
What is a tablet?
Solid oral dosage form composed of DRUG SUBSTANCE and EXCIPIENTS compressed from powder into a solid.
What are four (4) types of tablets?
- Oral tablets for ingestion
- Tablets used in oral cavity (oral release)
- Tablets administered by other routes
- Tablets used to prepare solution/suspension
What are five (5) advantages of tablets?
- Accurate and uniform dose
- Superior stability
- Ability to modify drug release
- “Easy” to mask taste
- Economical
What are three (3) disadvantages of tablets?
- Large tablet size may be difficult to SWALLOW.
- Poor FORMULATION may cause therapeutic FAILURE – disintegration and dissolution as rate limiting steps.
- Properties of API may cause ‘COMPRESSION PROBLEMS’ resulting in non-uniform dose.
What are eight (8) types of excipients?
- Binders
- Disintegrants
- Lubricants
- Anti-adherents
- Fillers/diluents
- Glidants
- DISSOLUTION enhancers/retarders
- Miscellaneous
What is a binder and give an example.
Helps particles stick together to form granules.
Ex. Starch
What is a disintegrant and give an example.
Helps tablet break apart in GI.
Ex. Sodium starch glycolate.
What is a lubricant and give an example.
Reduce friction between wall and die cavity (manufacturing machinery).
Ex. Magnesium stearate
What is an anti-adherent and give an example.
Reduce sticking of granules to punch or die cavity (manufacturing machinery).
Ex. Talc
What is a filler/diluent and give an example.
Increase bulk of formulation to a convenient size for compression.
Ex. Lactose
What is a glidant and give an example.
Improve flow of powder mixture.
Ex. Silicon dioxide
What is a DISSOLUTION enhancer/retarder?
Control release of drug
What are four (4) examples of miscellaneous excipients?
- Wetting agents
- Flavoring agents
- Coloring agents
- Antioxidant
What are six (6) considerations for the CHOICE of an EXCIPIENT in a DRUG FORMULATION?
- Delivered dose
- Route of administration
- Desired release characteristics
- Properties of drug
- Properties of excipient
- Manufacturing requirements
What are four (4) criteria for a substance to be used as an excipient in a drug formulation?
- Generally Regarded as Safe Status
- Available
- Physiological/Biological Stability
- Cost effective
What are three (3) FUNDAMENTAL properties of particles?
- Size
- Shape
- True density
What are five (5) DERIVED properties of particles?
- Bulk density
- Porosity
- Flow
- Cohesion/adhesion
- Surface area
What are seven (8) UNIT OPERATIONS in tablet manufacturing?
- Mill (API)
- Screen (EXCIPIENT)
- Blend/Mix
- Granulate (SOLVENT)
- Blend/Mix (EXCIPIENT)
- Compress
- Coat
- Package (CONTAINER)
What is the function of milling?
To reduce particle size and size variation.
What are four (4) ways to reduce particle size with milling?
- Compression
- Abrasion
- Shearing
- Impact
What are three (3) examples of milling equipment?
- Ball Mill
- Hammer Mill
- Attrition Mill (high velocity air)
What are three (3) potential failure modes of milling?
- Reduce size too much or too little
- Generate static electricity (explosion risk)
* *3. Induce physical or chemical changes (from heat or mechanical stress) [ex. Gabapentin stability reduced with increased processing]
What is the function of blending/mixing?
Content uniformity
What are three (3) forces acting during blending/mixing?
- Acceleration [mechanical] forces
- Gravitation forces
- Cohesive forces
What are four (4) approaches to blending/mixing?
- Trituration (mortar and pestle)
- Spatulation (geometric dilution)
- Tumbling (container moves)
- Stationary mixer (container does not move; blade moves)
What is the most effective example of a tumbling equipment?
V-blender
What are three (3) examples of stationary mixers?
- Hobart mixer (kitchen aid type)
- Ribbon blender (ribbon-shaped blade)
- Helical flight (conical rotating screw)
What are four (4) possible mixing failure modes?
- Difficulty with poorly flowing/highly cohesive powders.
- Over mixing can cause poor lubrication
- Non-uniform mixing of low dose drug
- Segregation (demixing of powder during later unit operation)
What is the function of granulation?
Create a compressible conglomerate of API and excipient
What are three methods of granulation?
- Direct compression
- Dry granulation
- Wet granulation
What are three (3) considerations for choosing a granulation method?
- Flow
- Compressibility
- Compactibility
When can direct compression be used?
Flow, compressibility and compactibility of drug are all GOOD.
When can dry granulation method be used?
Only FLOW of drug is poor.
When must wet granulation method be used?
When any attribute besides FLOW is poor.
What is the function of compression?
Bind powder into solid.
What is the physical basis for tablet formation by compression?
Formation of lasting areas of TRUE CONTACT between particle surfaces.
What are four (4) steps in the compression cycle?
- Fill the die
- Adjust the weight
- Compress
- Eject
What are three (3) examples of compression machinery?
- Hydraulic Tablet Machine
- Rotary Tablet Machine
- Multi-punch Tablet Machine
What are two types of poorly formed tablets?
- Capped tablet (separation of crown from main body)
2. Laminated tablet (separation into distinct layers)
What are four (4) processing problems in tablet compression?
- Picking/sticking (adhesion of powder to machinery)
- Mottling (unequal color distribution)
- Whiskering (cracking and chipping)
- Weight variation
What are three (3) properties of TABLETS AND their relationship to the amount of COMPRESSION FORCE
- Apparent porosity (inversely proportional)
- Hardiness (directly proportional)
- Disintegration time (directly proportional)
What are five (5) potential reasons for coating a tablet?
- Mask taste, odor or color of drug
- Control release of drug
- Reduce interaction between incompatible ingredients
- Protect tablet from gastric environment
- Enhance compliance
What are four (4) components of a coating mixture?
- Polymer
- Plasticizer
- Colorant
- Solvent/Dispersing agent
What are five (5) attributes of a polymer film (coating) former?
- GRAS status
- Soluble in [a] solvent of choice/[b] solution pH
- Resistant to cracking
- Provides adequate protection from moisture, light, heat, etc.
- No taste, color or odor (unless desirable).
What are the disadvantages of sugar coating a tablet?
- Multistep
- Labor intensive
- Time consuming
What are three (3) types of polymer film coatings?
- Fast dissolving
- Sustained release/Extended release
- Enteric/Delayed Release
What are two (2) examples of non-enteric film forming polymers?
- Ethylcellulose
2. Hydroxypropylcellulose
What are two (2) examples of enteric film forming polymers?
- Cellulose acetate phthalate
2. Cellulose acetate trimelletate
What are two (2) examples of water-soluble plasticizers?
- Glycerin
2. Propylene glycol
What are two (2) examples of water-insoluble plasticizers?
- Glyceryl citrates
2. Dialkyl phthalate
What are two (2) coating methods?
- Pan coating
2. Air suspension (fluidized-bed) coating
What are five (5) film defects?
- Sticking and picking
- Roughness
- Orange peel
- Bridging and Filling
- Cracking
What causes sticking and picking of tablet coating and how is it remedied?
- Caused by over-wetting
2. Remedied by reducing coating spray rate.
What causes roughness of tablet coating and how is it remedied?
- Caused by improper coalescence of polymer
2. remedied by using fluidized-bed coater
What causes orange peeling of a tablet coating and how is it remedied?
- Caused by inadequate spreading of coating solution
2. Remedied by diluting the coating solution
What causes bridging and filling of tablet coating and how is it remedied?
- Caused by coating solution drying too rapidly
2. Remedied by adjusting drying temperature
What causes cracking of tablet coating and how is it remedied?
- Caused by insufficient tensile strength of polymer
2. Remedied by using higher molecular weight polymer (or combination of polymers) or different plasticizer.