Lecture 17: Polymers Flashcards
Functions of polymers in pharma products
-controlled delivery
-scaffolds for tissue engineering
-transdermal patches
polymer function in oral drug delivery
-coating
-binders
-taste maskers
-protective agents
Polymer
-large molecule made of many small repeating units
-macromolecules and plastics
macromolecules
-any large molecules
-polymers are a subset (repeating units)
Plastics
-can be molded, cast, extruded, draen, thermoform, laminated into product
Polymer basics
-natural vs synthetics
-name
-structure
-synthesis
-molecular weight
-crystalline vs amorphous
-glass transition temp
-mech properites
-applications
Nitrocellulose (1845)
-guncotton
-first semi sythentic polymer
-accidentally made in a kitchen
Bakelite
-first synthetic polymer based on phenol and formaldehyde
-strong and durable
-sub for auto/electric parts
Natural polymers
-nucleic acids (DNA, RNA)
-proteins
-polysaccharides
Synthetic polymers
-polyethylene, poly-n
-nylon, silicon rubber, rayon, teflon, kevlar
Polymer name
-poly + (repeating unit)
Polymer structure
-homo
-random co
-alternate co
-block co
-graft co (extends as branch off other polymer)
Linear polymers
Cross-linked polymers
Polymer unit expression
-building block is 2 Carbons not one
Polyacrylamide
-run large polymer across network
-surfactant
-run SCC
-electrophoresis? idk
-polymers movement on gel based on density
Polymer synthesis methods
-condensation polymerization
-addition polymerization
Condensation polymerization
-step polymerization
-2 or mote bifunctional monomers w dif functional groups react
Addition polymerization
-free-rad polymerization
-chain polymerization
-initiation by adical
-propogation
-termination by inert molecule
-keep recruiting monomers
-polyacrylate and polysyrene
Molecular weight of polymers
-Mn (number average)
-Mw (weight average
-monodispersed or polydispersed
monodispersed
-Mn=Mw
-Mw/Mn =1 polydispersity
polydispersed
-Mw»_space; Mn
-Mw/Mn»_space;1 polydispersity
-broad distribution in weight
Crystalline
-linear
-can pack tightly
-T<Tm
-sharp Tm
-food barrier to diffusion
-durable
Amorphous
-more common
-irreg structure
-forms glas at T<Tg
-softens over wide temp range
Glass transition temperature (Tg)
-temp range where a polymer changes from a hard/rigid/glassy state to more compliant/rubbery state
Polymers at T «Tg
-hard, stiff, glassy
polymers at T»_space; Tg
-rubbery and may flow
Chewable dosage forms
-polymer with Tg close to 37
-gum is softened at mouth temp
-chewing release nicotine release
-parking slows release
Factors inc Tg
-polymer long length
-bulky side chains
-crosslinking
-plasticizers
Plasticizers
-molecules that inc entropy and mobility of polymer chains
-lower Tg when in polymer products
-water example
Mechanical properties of polymers
-stress vs strain (slope) (stiffness)
-AUC = touughness
elastic polymers
-linear stress vs stain curve up to a breaking point
Rubbers or elastomers
-may deform 10-15 times original lengths
Hydrogels
-crosslinked network of hydrophillic polymers
-swell rapidly in water
-retain large volume of water in structure
Hydrogel types
-chemical gels (covalent)
-physical gels (H bonds, interactions)
Hydrogel swelling
-chain-water interaction
-electostatic repulsion
-osmotic forces
Polymers in dosage forms
-cellulose-based
-hydrocolloids
-water-soluble
-water-insolube
Cellulose based polymers
-ethylcellulose
-carboxymthyl cellulose
-hydroxypropyl methy cellulose
Hydrocolloids
-alginic acid (thickening agent)
-chitosan (mucoadhesive)
water-soluble polymers
-poly(ethylene glycol)
-poly(vinyl alcohol)
water-insoluble polymers
-poly(lactic-co-gycolic acid)
-polylactic acid
-controlled drug release
