D5 and D6. Tablet manufacturing Flashcards
(47 cards)
Oral drug formulationsmain considerations & challenges?
-oral administration restricts formulation size and appearance:
eg size to swallow, taste and palatability (children medicines)
-formulation must disintegrate in GI tract in appropriate time:
use of optimized excipients (disintegrants) and fabrication technology (coating)
-formulation must make drug available for absorption:
drug needs to be in dissolved state during its transit through the gastrointestinal tract for absorption to occur | consider appropriate drug solubilisation approaches
-formulation needs to address drug sensitivity to environment in GI tract:
eg protection by enteric coating, local pH buffering or enzyme inactivation
-formulation needs to address drug absorption properties from GI tract:
eg use of absorption enhancers and gastroretentive formulations to overcome absorption window issues
tablet requirements for an ideal oral solid dosage form
-uniform drug content (reproducible dose)
-drug must remain stable during production and storage
-drug must be bioavailable (formulation reliably releases drug in GIT)
-formulation is robust during handling (by patient as well)
-easy and cost effective to mass produce
-pleasant to take – appropriate to patient group
what can be achieved by tablets?
-accuracy in dosing
-stability (in comparison to liquid formulations)
-release of drug in GIT
-robust on handling
-ease of manufacture (‘mature’ technology in pharmaceutical industry)
-convenient administration and high patient compliance
Schematic of tableting process?
one note
requirements for Schematic of tableting process?
-uniform flow of the powder (prerequisite for uniform tablet weight)
-no powder segregation (prerequisite for uniform drug content )
-die cavity uniformly filled (prerequisite for uniform drug content)
-powder compressibility (to remain as tablet once the pressure is removed)
-lubricability (no sticking to the die cavity and punches under pressure)
volume of powder filling die cavity determines?
tablet weight & drug dose
most powders cannot be compressed into tablet, why?
they do not posses the required properties – compressibility – hence need excipients with compressibility properties
ways to make tablets?
one note
what is granulation?
build up of small particles into a larger aggregates with the aid of a binding agent or mechanical force
benefits of granulation?
-spherical and free-flowing granulate particles
-more uniform size distribution
-improved flow
-reduced segregation
-allows volume dispensing
-improved compression
-binder introduction
improved strength of final granule can be achieved by addition of?
binding agent (e.g. binder excipient)
Unit operations in tabletting via wet granulation?
one note
advantages of spray granulation / fluid bed wet granulation?
one step procedure - includes granulating and drying | control of spraying and drying rate critical
ONE NOTE
what is dry granulation (also called dry compaction) ?
powder blend is compacted by applying mechanical force onto the powder
Compaction force applied in: either specialized tabletting machine (‘slugging’) or by roller compaction equipment
ONE NOTE
Dry granulation (also called dry compaction) used for?
moisture sensitive materials
heat sensitive materials. wet granulation process cannot be used for moisture sensitive or heat sensitive materials.
Disadvantages of dry granulation (also called dry compaction)
-can result in granules with low porosity
-dust creation
-special equipment required
Describe direct compression
direct compression process is based on availability of an excipient that has physicochemical properties required for tabletting called: DIRECT COMPRESSION EXCIPIENTS
ONE NOTE
desired properties of direct compression excipients to satisfy requirements:
-good flow
-good compression properties
-particle size similar to that of active drug – to avoid segregation during processing (an issue)
-high bulk density – otherwise thin tablet is produced
-physically and chemically stable in contact with moisture, heat and air
-chemically inert
Describe compressibility
-most powders cannot be compressed into tablet – they do not posses the required properties – compressibility
-typically 20-30% of poorly compressible drug can be incorporated into tablets made by using direct compressible excipient
Describe directly compressible excipients
-Commercially available, speciality ingredients developed by supplier (by patented processes)
-Examples: Ludipress, Emdex, Avicel, Tabbletose - different forms of lactose, cellulose, or starch – modified through processing to acquire required properties for direct compression
ONE NOTE
SUMMARY OF DIFFERENT PROCESSES IN TABLET PRODUCTION
ONE NOTE
Compression stages of powders into tablet
ONE NOTE
Describe compression
-compaction of powdered material due to applied pressure
-in tabletting granulate in the die is compressed between an upper and a lower punch to consolidate the material into a single solid matrix
subsequent events occurring during compression:
-filling of die
-particle rearrangement
-elastic deformation at points of contact
-fragmentation and/or plastic deformation
-bonding
-plastic deformation of the solid body
-decompression and ejection
