Lecture 6+7: Tablets Flashcards
immediate-release tablets
-release meds with no rate-control
extended release tablets
-release meds over extended period
rapidly disintegrating or dissolving tablets
-disintegrate in mouth within 1 min, some within 10 secs
Tablet manufacturing processes
-wet granulation
-dry granulation
-direct compression
direct compression
-tablet manufacturing process
-less steps
-no granulation
-GOOD flowability, content uniformity, and compressiblity
Tablet manufacturing processes:
- die filling
- tablet compression
- tablet ejection
Excipients for tablets
-diluents/fillers
-binders
-disintegrants
-glidants
-lubricants
-Mg stearate, talc, sodium stearyl fumarate
Diluents/fillers
-add bulk to formulation for size
-lactose, mannitol, starch
binders
-promote adhesion of particles
-allow granulation to be prepared and maintain integrity of the final tablet
-water, alcohol, starch paste, sucrose syrup, PVP, MCC
more binder in tablets leads to
-harder tablets
-slower disintegration time
-slower dissolution rate
disintegrants
-promote breakup of tablets after administration to smaller particles for ready drug availability
-starch, cellulose derivatives
Glidants
-enhance flow of material into the tablet dies
-collodial silicone dioxide, talc
Lubricants
-prevent fill material from sticking to punches and dies
-decrease adhesion, friction, and punch/die wear
-Mg stearate, talc, sodium stearyl fumarate
Negativve effects of over-lubrication with Mg stearate
-reduce tablet hardness or tensile strength
-slow dissolution due to hydrophobic nature of Mg stearate
-some drugs incompatible with Mg stearate
Tablet coating functions
-provide special traits of drug release (enteric coating)
-protect drug from environment
-mask taste
-improve swallowing
-identification
Types of tablet coatings
-sugar
-film
-compression
Sugar coating
-tablets with sugar layer
-water soluble
-dissolves quickly
-usually round and smooth
-like M&Ms (advil)
-enteric
Cons of sugar coating
-multi steps: sealing, coating, smoothing, polishing
-time consuming
-need expertise
-increases tables size and weight up to 50%
Film coating
-thin film of polymeric materials
-single stage
-better for controlled release
-breakable
-via spraying
-polymer in liquid eith pigments and plasticizers
-drying of liquid leaves film coating around tablet
immdiate-release Film coating
-nonfunctional
-soluble in water
modified release Film coating
-functional
-delayed release (enteric)(SOLUBLE only pH>5)
-extended release (NOT soluble in water)
Film coating formation
-rapid solvent evaporation
-deposit and spreading of coating liquid droplets on tablets
=sticky residue
-coating polymers get more viscous as evaporation
-complete drying occurs slowly
Film coating requirement
-liquid needs to be atomized into droplets
-tablets need good mixing and agitating (each tablet needs to pass thru spraying zone)
-hot air to evaporate solvent
-exhaust to remove dust and evaporated solvent
Film coating formulations
-polymer
-plasticizer
-colorant
-solvent
Polymer film coating formulation
-solubility determines selection for immediate/modified release
-low viscosity desired
-permeability masks taste, limits exposure to air, modifys release
Polymer film coating mechanical properties
-film strength: resist mechanical stress
-film flexibility: minimize cracking
-film adhesion: ensure product integrity
Polymer coatings for immediate release
-cellulose derivatives (HPMC)
-vinyl derivatives (PVP and PVA)
Polymer film coatings for modified release
-cellulose derivatives: EC, CA
Plasticizer film coating formulation
-reduce brittleness
-enhance flexibility of polymers
-PEG, esters
Colorant film coating formulation
-water soluble (dyes) and INsoluble (pigments)
-insoluble better bc better stability, opacity, and covering power
-iron oxide (red)
-titanium dioxide (white)
Solvent film coating formulation
-organic solvents better bc fast drying
-meant for modified release that needs to be protected from environment
Film coated products
-uniformity
-NO visual or functional defects
-compliant with specifications
Coating defects
-bad uniformity
-poor penetration
-not enough passes thru spray zone
-low mech strength
-bad adhesion
-surface too wet
-color inhomogeneity
-delamination/peeling
Tablet Quality Control
-general appearance (size/shape/markings)
-drug content and release (weight, disintegration, dissolution, stability, hardness, friability)
Crushing strength
-tablet hardness
-4-6kg
friability
-tablet mass loss during drum rotating at 20 bpm for 100 roations
-max weight loss < 1%
Extended-release tablets
-allows reduction in dosing frequency from that necessitated by conventional dosage form
Pros of extended release
-less fluctuation in blood levels
-frequency reduction in dosing
-enhanced convenience and compliance
-reduction in adverse side effects
Types of extended release dosage forms
-coated beads, granules, and microspheres
-matrix tablets
-osmotic pump tablets
matrix tablets
-embed drug slowly in dissolving matrix with polymer HPMC as metrix material
-tablet core and gel layer
osmotic pump tablet
-semipermeable membrane
-osmotic core with drug
-water
-delivery orifice
Considerations of using modified-release
-do NOT crush or chew
-NOT interchangable with immediate release version
-some materials may not be dissolved = shows up in stool
