Polymers Flashcards
Polymer
many parts
Large molecule made up of many small repeating units
Also called macromolecules (not always repeating units)
Monomer
small molecule that combines with the same type of molecule or different types to form a polymer
Polymer structure
Long
Repeating
Dimer, trimer, tetramer, and pentamers
Polymers are classified based on
Origin (natural or synthetic)
Biostability (biodegradable)
Reaction (addition or condensation)
Arrangement of monomers
Natural vs synthetic polymers
N: proteins, carbs, DNA, RNA
S: polyester, polyamides
Biodegradable polymers
Made of monomers that are linked to each other via unstable function groups
Non-biodegradable polymers
Excreted in intact form or stay in the body for a long time
Homopolymers
Formed by identical monomeric units
Copolymers
Formed from more than one monomer type
Block or graft copolymers
Various arrangements of the monomers in teh copolymer molecules
Properties of polymers
Chemical reactivity depends on chemistry of the monomers
Depend on way the monomers are put together
Monodispersed Polymers
Polymer sample have the same molecular weight
All molecules will have the same chain length
Proteins, DNA
Polydispersed
Polymer sample has molecules of different chain lengths with a range of weight
Synthetic polymers
Gel properties
Cross-linked systems
Type 1 Gel
Irreversible systems with 3D network formed by covalent bonds
Type II Gels
Heat-reversible; head together by hydrogen bonds
Gel Point
Temperature at which a polymer solution starts to form gel
Implants
Inserted in the dehydrated state and let the polymer swell to fill a body vacity or to give a form to the surrounding tissue
Vehicles for antibodies and surgical sutures
Bio-responsive drug delivery systems
Swelling properties of a polymer gel can be changed by heat, pH or application of electrical current to develop
Carbomer or Carbopol
Suspending agents
Celluloes derivatives
Prolongs the action of medicated eye drops and is employed as artificial tears
Dextran
Plasma expander –> maintain blood volume
Wound-dressing
Edema
Ion-exchange resins
Pholtex
Prolongation of drug action
Lipid lowering agents: Bile acid sequestrants
Cholestyramine, colestipol, colesevelam
Drug formulations
Film coatings
Matrices
Rate-limiting membranes and devices
