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137 Cards in this Set
- Front
- Back
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Polymers are expensive and reactive
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False. Generally cheap and Inert.
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Polymers have low surface to volume ratio. T or F
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F High surface to vol ratio
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Polymers are ____ at room temp
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solid
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examples of rubbers
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Processability Styrene-butadiene (SBR)Polybutadiene (PB)Ethylene-propylene (EPDM) Polychloroprene (CR)Nitrile (acrylonitrile and butadiene)Butyl (isobutylene and isoprene)Polysiloxanes (silicones)PolyurethaneTire
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Tg
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glass transition temperature
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Examples of fibers
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Cellulose acetate Viscose rayon Polyesters Polyacrylonitrile PolypropyleneNylon (66)Carbon Aramid Kevlar
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Rubber- ___ Tg
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Low
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Rubber- ____ elasticity
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high
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Rubber- ____ Strength and Durability
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high
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Rubber- ____ fatigue
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high
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Rubber - ____ resistance
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high
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Four properties of fibers
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High strength
Thermal stability (ironing) Spinnability Crystalline |
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polymer has a vapor phase
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False
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polymer molec wt =
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Molecular Weight = DP ×Mw of the Monomer (DP=degree of polymerization)
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3 steps polymerization
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initiation
propagation termination |
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what reacts to make macroradical in
addition polymerization |
radical + double bond (monomer)
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what is condensation polymerization?. 1 what type of rxn
2 what is released at the end |
Condensation polymers are any kind of polymers formed through a condensation reaction, releasing small molecules as by-products such as water or methanol, as opposed to addition polymers which involve the reaction of unsaturated monomers. Types of condensation polymers include polyamides, polyacetals and polyesters.
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what polydiversity >>1 means
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>>1 means many length polymers (polydispersed).
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polydiversity =1 means
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=1 means same length (monodispersed)
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Topology: Linear vs ____
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branched
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Isomerism means molecule can be ___ or _____. This means that morphology can change from _____ to ______.
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cis, trans, amorphous, crystalline
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stereoisomerism may vary with ____
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temperature
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isotactic
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polymer stereoisomerism where funct group has cis repeats (same side). high Tg
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Syndiotactic
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polymer stereoisomerism where funct group has trans repeats (opposite sides). medium Tg
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Atactic
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polymer stereoisomerism where repeats of funct groups may be random. low Tg
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5 types of Order of Repeating Units
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Homopolymer
Random Copolymer Alternate Copolymer Block Copolymer Graft Copolymer |
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Homopolymer
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same repeating polymer
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Random Copolymer
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a diff monomer placed at random locations of the polymer
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Alternate Copolymer
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a diff monomer placed intermitantly
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Block Copolymer
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a diff monomer unit placed continously extending off a polymer
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Graft Copolymer
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a diff polymer crosslinked to a polymer
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Tg
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glass transition temp
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Tm
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melting temp
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Td
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Decomposition Temperature
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order of temp of Thermal Transitions of Polymers
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Td> Tm> Tg
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The temperature at which a glassy polymer softens into a viscous liquid or rubbery phase
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Glass Transition Temperature (Tg)
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The temperature at which the ordered regions of a crystalline polymer melt
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Melting Temperature (Tm)
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The temperature above which polymer degrade
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Decomposition Temperature (Td
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In a graph of Temp vs deltaH. Tg is a ____ and the rxn is _______
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sigmoidal curve down. endothermic
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In a graph of Temp vs deltaH. Tm is a ____ and the rxn is _______
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trough. endothermic
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In a graph of Temp vs deltaH, Td is a ____ and is _____ .
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peak. exothermic
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Crystalline is ____ to _______ transition and is _______ order transition. It is associated with T_.
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Solid, melt. first. Tm
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Amorphous is a ____ to _______ transition and is _______ order transition. It is associated with T_.
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Glass, rubber. second, Tg
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reguarding anisotrophy and the free volume concept, something ______ has more free volume than something ______.
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isotropic , radial ORlongitudinal
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amorphous stuff is ____ while crystalline is ____ (reguarding anisotrophy)
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isortropic, radial OR longitudinal
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A polymer that is not very isotropic has ___ barrier properties, ___ stiffness and ___ strength
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stronger, more, more
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A polymer that is not very isotropic has ___ optical clarity, ____ solubility, and ___ toughness.
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lower , lower, more
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A polymer that is very isotropic has _____ solubility, ____ stiffness, and ___ optical clarity.
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higher, lower, more
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Radial or Longitudinal has more free volume
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both the same. however isotropic has more free volume (remember curly hair)
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Tg is ____ with bulkier side groups and ____ with nonpolar side groups.
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higher, lower
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The mechanical property of glass -> rubber increases with ___
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temperature
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diff btw plastics and elastomers
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plastics have a range closer to glass mechanical property and elastomers are in a range closer to rubber mechanical property
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for plastics, RT is ___ than Tg
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lower
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for elastomers, RT is ___ than Tg
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higher
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a straight chain polymer is more flexible and gives a ___ Tg
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lower
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ring polymers have ___ Tg than straight chain polymers
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higher
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Tg is higher with ____ free volume and ____ hindrance.
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small, high
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A very crosslinked polymer has ___ Tg while a slightly crosslinked polymer has ___ Tg.
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high, no
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a bunch of added plasticizers ___ the Tg of a polymer
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lower
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when are plasticized dosage forms used
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when you need drug released at different times (ER)
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Mn is avg molec weight that is based solely on the ______
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mean
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Mw is avg molec weight that incorporates _____
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polydiversity
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Mw/Mn >1
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polydiversity
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Mw=
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(ΣMi2 x Ni ) / (ΣMi x Ni)
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Mn can be used to for Colligative properties, Freezing point depression, Osmosis,and End group analysis, while Mw can be useful for _ _
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Light Scattering
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the working range of a polymer is before a ______ curve and _____ curve intersect
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viscosity, mechanical
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a higher modulus means more _______ is required to make a _____
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force, deformation
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tough plastics have a _____ modulus compared to fibers
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low
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fibers have a ____ modulus compared to rubbers
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high
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rubbers have a ____ modulus compared to tough plastics
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low
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high Mn leads to lower ___
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polydiversity
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drug degradation _____ bioavailability
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decreases
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expiration date is supposed to show stability and potency of ____
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90% or more
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what is the purpose of storing certain drugs in dry form, when they have to be in solution to be active when they are administered (prodrug)?
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some drugs may instantly hydrolyze producing toxins. they must be reconstituted from dry form and used within 24 hrs.
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Neupro(rotigotine) transdermal patches were recalled cuz they werent stable. why
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the drug crystallized on the patch and the drug was ineffective since it couldnt pass into the skin
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stability is most often compromised due to reactions with 3 things. ____ can also cause instability
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rxns w moisture, oxygen and light. polymorphism (physical change)
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Triangle of stability
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Identity
Purity Potency |
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Optical forms transformation (levo, dextro)
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racemization
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Drug reaction with light (UV, IR)
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photolysis
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Liquid/gas phase changes, odor or taste loss
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vaporization
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Drug is adsorbed into its container (cause of instability
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adsorption
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:Hydration and Dehydration are example of _________ and ________ (drug instability causes)
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Absorption and Desorption
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Tend to form sediments on standing that must be re-suspended by moderate shaking
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suspension
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Phases tend to separate on standing. Must be re-dispersed by moderate shaking
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emulsions
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Reaction of –OH and –COOH of different molecules makes
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ester
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Reaction of –OH and –COOH of a same molecule makes
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lactone
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Reaction of –COOH and –NH2of different molecules makes
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amide
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Reaction of –COOH and –NH2of same molecules makes
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lactam
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Reaction of two –COOH makes
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anhydride
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Anhydrides are hydrolyzed fast with __ catalyst
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no
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Ester hydrolysis to acid and alcohol is __________ under alkaline condition (saponification)
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irreversible
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Ester hydrolysis to acid and alcohol is _________ under acidic condition
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reversible
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Amides are ____ stable than esters
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more
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Rate of OH-catalyzed hydrolysis of amides is ________ than Rate of H-catalyzed hydrolysis of amidesA
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greater
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Catalysis by H+ or OH-is called
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specific acid-base catalysis
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Buffer ions such as acetate or citrate can catalyze degradation, this is called
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general acid-base catalysis
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Phenols, aromatic amines, aldehydes, ethers and unsaturated aliphatic compounds
are ______ upon exposure to air or certain chemicals |
oxidized upon exposure to air
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0.0002M copper ion _______ the rate of vitamin C oxidation by a factor of 105
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increases
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Primary antioxidants.
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Free Radical Scavengers which Provide electrons to free radicals
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Secondary antioxidants
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Oxygen Scavengers These undergo auto oxidation by consuming oxygen (preferred for enclosed bottles)
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Tertiary antioxidants
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: Ion Scavengers Chelating agents react with ions responsible for initiating oxidation reactions
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Hydroxyl ions are _________ nucleophiles than water, means drug degrades ______ in OH rich solution than in water (in alkaline solutions)
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Hydroxyl ions are _________ nucleophiles than water, means drug degrades ______ in OH rich solution than in water (in alkaline solutions)
stronger, more |
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pH adjustment is necessary to achieve optimum stability in dosage forms, but why should you try to minimize the buffer?
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buffer is involved in general acid-base catalysis of degradation (by hydrolysis) of the drug
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Oxidation is promoted by oxygen and initiated by heat, light and metal traces which produce ___ _____.
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free radicals
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what is used are used in pharmaceuticals to inactivate free radicals by producing relatively stable products
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Free radical scavengers
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what is generated by ionizing irradiation, photolysis, metals and peroxides
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radicals or free radicals
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Primary antioxidants (which are Free Radical Scavengers) do what
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Provide electrons to free radicals
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Secondary antioxidants (which are Oxygen Scavengers) do what
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These undergo auto oxidation by consuming oxygen (preferred for enclosed bottles
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Tertiary antioxidants (which are Ion Scavengers) are _______ agents.
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chelating
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Chelating agents react with ____ responsible for initiating oxidation. These are ______ antioxidants. They are known as ____ scavengers.
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Chelating agents react with ((ions)) responsible for initiating oxidation. These are ((tertiary)) antioxidants. They are known as ((Ion Scavengers)).
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3 types of antioxidants
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primary (free radical scaverngers), secondary (oxygen scavengers), tertiary (ion scavengers)
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Light-catalyzed oxidations and reductions involve what kind of intermediates
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radicals or free radicals
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Light instability can happen in a solution and but not to something in solid state. T or F
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F. Light instability can happen in both solution and solid states
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Light degradation in dilute solution is ____ order reaction.
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Light degradation in dilute solution is ____ order reaction. first order rxn
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Light degradation to very concentrated solutions show a _____________ order rxn
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Light degradation to very concentrated solutions show a _____________ order rxn. pseudo-zero order rxn
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In a photostability test, if a drug has a half life for over 5 hrs it's considered ___
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stable
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If half life is 4 minutes in a photostability test, what is the drug considered to be, in regard to stability?
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very unstable
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T or F. racemization is only catalyzed by acid
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F. racemization is catalyzed by asses and bases. (A notable exception is chlorthalidone which undergoes spontaneous racemization)
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T or F. Drug excipients do not interact with active drug.
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F. Drug-excipient interaction affect stability and may lead to unwanted products or degradation.
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T or F. Protein structures may lose activity as a result of change in primary structure.
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F. Protein based drugs may lose activuity as a result of a change in superstructure, which is secondary, tertiary, quarternary
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T or F. Shear rate may affect protein suprastructure.
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T. therefore drugs may lose stability during treatment and processing (grinding, mixin )
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Suspensions follow ____ order kinetics. How fast do they degrade in comparison to solutions?
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ZERO order kinetics. Suspending a drug into a matrix reduces degradation. Thus, suspensions are MORE stable than Solutions. The half life of suspensions decreases over time!
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Solutions follow _____ order kinetics. How fast do they degrade in comparison to suspensions?
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1st order Kinetics. The half life remains constant over time. For suspensions the half life decreases (slower degradation). Solutions have FASTER degredation.
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Solvent effect can be large, so why is it not so important for pharmacy anymore?
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Solvent effect can be large, so why is it not so important for pharmacy anymore?
There is limited use of solutions in pharmaceutical dosage forms. (The exception is drugs for critical diseases, such as cancer drugs) |
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T or F. Nitroglycerin or quinidine, drugs pakaged in PVC infusion bags, will remain in the same concentration after a week in room temperature.
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F. There is ADSORPTION. This is a result of partitioning into hydrophilic/hydrophic. The hydrophobic part of the drug will interact with the surface of the plastic of the PVC bag.
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Flavors used in drugs contain ketones, aldehydes, esters, and low molecular weight alcohols which have _____ vapor pressure. Drugs with ____ vapor pressure may see significant loss during storage.
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high. high
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T or F. High vaporization may cause non-uniformity of drugs.
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T
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In regard to polymorphism, the ________ form of drugs is more stable, however the ______ form of drugs is more stable due to pseudopolymorphism.
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Crystalline, amorphous
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what causes pseudopolymorphism
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hydration and dehydration
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how may amorphous form become crystalline
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by absorbing moisture
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if drugs are below __ % potency, they are expiered
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90
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Long polymer chains have ____ Tg than short polymer chains.
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bigger
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T or F. The more stable form (reguarding polymorphism) of a drug is always optimal.
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F. In the recalled Neupro patches, for example, the crystalized form of rotigotine wont diffuse through the skin. It is not the optimal form since it cant be administered. In this case, the amorphous form is prefered.
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If a drug is hydrolyzable, which form of the drug is the worst form of storage to maintain drug stability
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solution
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aggregation refers to ______ particle size while nanotechnology refers to decrease in particle size. The whole idea of nanotechnology for drugs is to increase the _____ _____ by decreasing particle size.
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aggregation refers to ______ particle size while nanotechnology refers to decrease in particle size.
The whole idea of nanotechnology for drugs is to increase the _____ _____ by decreasing particle size. increase, surface area |
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A nitrile hydrolyzes to an amide under ____ conditions while it hydrolyses to a carboxylic acid under _____ conditions.
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A nitrile hydrolyzes to an amide under ____ conditions while it hydrolyses to a carboxylic acid under _____ conditions.
mild, extreme (heating acid or base solutions) |
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what is a commonality in structure of photo-instable molecules
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they contain benzene groups
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