Exam 1 Polymers Flashcards
What are polymers such as hydroxypropyl methylcellulose (HPMC), hydroxypropylcellulose (HPC), polyethylene glycol (PEG), povidone (PVP), and sodium carboxymethylcellulose (CMC) used for?
Water soluble polymers used in tablet coating
Some water-soluble polymers as well as acacia, gelatin, and sodium alginate are used for what?
Binders in tabletting
Cellulose acetate phthalate, hydroxypropyl methylcellulose pthalate, and copolymers of methacrylic acid and it’s esters are used for?
Enteric coating
Generally, polymers are used to ______ suspensions and opthalmic solutions, as protective _______ to stabilize emulsions and suspensions, and to form water-soluble jellies and ointment bases
thicken; colloids
What polymer has the widest range of application in pharmacy?
Gelatin
Linear polymer where backbone is a long chain of covalently bonded carbon, silicon, or sulfur atoms (same atoms)
Homochain polymer
Backbone contains more than one atom, which also includes purely inorganic polymers
***Side note: Polymers are usually organic
Heterochain polymer
A repeat unit, or mer, of a polymer
Monomer
The number (n) of repeat units per macromolecule is called?
Degree of polymerization
Process is started by a free radical formed by thermal decomposition of an initiator such as benzoyl peroxide
Addition or chain-reaction polymerization
Where does a free radical add to a vinyl monomer (compound with unpaired electron)?
Double bond
One monomer is involved and include many naturally occurring polymers such as cellulose and rubber
Homopolymers
______ are copolymers of different amino acids
Proteins
Two repeat units that join together following no sequence in a chain that are used to make containers for parenteral solutions (AAABBABABBBAAB)
Random copolymers
Polypropylene sulfone is an example where copolymerization of propylene and sulfur dioxide occurs (ABABABABABAB)
Alternating copolymers
Include surfactants and fecal softeners where there are long sequences of the same monomer
Block copolymers
Most linear and branched polymers are ______, which means they can be softened or melted by heat and dissolved in appropriate solvents
Thermoplastic
Esterification of two bifunctional monomers, ethylene glycol and terepthalic acid, produce a linear monomer. If small amounts of ethylene glycol are replaced by glycerin (trifunctional monomer), the resulting polymer would be considered ________. If ethylene glycol is partially or completely replaced by glycerin, a _________ structure is produced.
Branched polymer; crosslinked (network) structure
Polymer in a soft solid or viscous state, that irreversibly changes into an infusible, insoluble polymer network by curing
Thermosetting polymer
These polymers are formed when a free radical removes a hydrogen atom from an existing chain, and produces another free radical. Gamma rays can also cause free radicals to occur
Graft copolymers
Sodium polysterene sulfonate suspension is an example of a _______-______ resin. In the GI tract, the resin swells and fluid freely permeates the swollen grain, exchanging K+ ions with Na+ of the resin
Cation-exchange
Cholesteryramine resin is an example of a _____-_____ resin, where it exchanges a Cl- ion with NO3- ions.
Anion-exchange
Calcium salts are ____ soluble than sodium salts
Less soluble
Test where absorbed weight of sodium bicarbonate solution is not less than 62g per g of resin
Absorbing power test
We don’t have enzymes to break ______ glycosidic bonds. We are able to break ______ glycosidic bonds.
Can’t: beta-1,4 glycosidic bonds
Can: alpha-1,4 glycosidic bonds
The number of hydroxyl groups per anydroglucose repeat unit that has been substituted. Pertains specifically to cellulose and starch derivatives
Degree of substitution
Unit that releases one molecule of H2O when polymerized
Anhydrose
DS values range from ___ - ____
0-3
A DS value of 0 means ____ ______.
A DS value of 3 means _____ _______.
No interaction
Three substitutions
DS is the ______ value over the entire sample
Average value
Molar substitution is used whenver…..
Hydroxylated derivatives of cellulose are produced
Molar substitution in hydroxyethlcellulose, for example, is the
Average number of ethylene oxide molecules that have reacted with one anydroglucose repeat unit
MS is always _____ than DS
Greater
Most ethoxylation occurs at the _____ hydroxyl group (2 ethylene oxide molecules on average)
Primary hydroxyl group
True or false: MS can exceed 3
True
Nature can’t tolerate randomization; therefore, small molecules and many biopolymers are ________
Monodisperse
Molecules that have different chain lengths and weight, where an average molecular weight is used, are known as _______
Heterodisperse
A sample of polystyrene made up of two monodisperse fractions have molecular of fraction A of 20,000 and fraction B of 100,000. Fraction A has in the sample, 3 times as many molecules as B. What is the number-average molecular weight? What is the weight-average molecular weight?
Number-average:
X(A) = nA / (nA + nB) so 3 / (3+1) = 0.750
X(B) then equals 1 - X(A) = 0.250
Mn = (0.750)(20,000) + (0.250)(100,000) = 40,000
Weight-average:
W(A) = 320,000 / (320,000 + 1100,000) = 0.375
W(B) = 1 - W(A) = 0.625
So
Molecular weight (Mw) = 0.37520,000 + 0.625*100,000
Mw = 70,000
Xanthan gum is a carbohydrate that can be used as
A suspending agent
Methycellulose is ______ soluble
Ethylcellulose is _______ soluble
Water-soluble
Alcohol-soluble
What does the 3350 stand for in PEG 3350?
Molecular weight
Microspheres have what effect on viscosity, and how does this affect the release of the compound?
Increases viscosity, causing extended release
What are carbomers?
Polymers of acrylic acid
True or False: In polyethylene glycols, the number indicates the molecular weight (PEG 1500), while in methylcellulose, the number indicates the viscosity of solution at certain concentrations (Methylcellulose 400)
True
True or False: Number of repeat units per macromolecule is called degree of polymerization, while the number of hydroxyl groups per anhydroglucose repeat unit that have been substituted is known as molar substitution.
False: the number of hydroxyl groups per anhydroglucose repeat unit that have been substituted is know as DEGREE of substitution
Molar substitution involves hydroxylated derivatives of cellulose
True or False: Poloxamer NF is an example of a block copolymer and sodium polystyrene sulfonate is an example of a crosslinked polymer
True
True or False: Cellulose and starch are both glucose polymers; however, they differ from each other in the type of 1,4 glycosidic bonds that link the glucose residues
True
True or False: In cellulose, the bond between the anhydroglucose units is a beta-1,4 glycosidic bond
True
Which of the following statements are FALSE?
- Polycarbophil is a bulk laxative. It swells extensively in the stomach, and minimally in the intestine
- Sodium polystyrene sulfonate is a cation-exchange resin
- Degree of substitution in cellulose and starch derivatives do not exceed 3
- Human serum albumin is a monodisperse polymer
- The value of the molecular weight of a polymer is dependent on the method used in its calculation
- Polycarbophil is a bulk laxative that swells extensively in the INTESTINE and minimally in the STOMACH
Which of the following statements are FALSE?
- Flexible bags of plasticized polyvinyl chloride are used to hold blood and intravenous solutions
- Polyethylene glycols are water-soluble based polymers
- Crosslinked polymers are thermosetting while most linear and branched polymers are thermoplastic
- Proteins are homopolymers
- Cholestyramine Resin USP binds sodium glycholate and other bile salts in the GI tract
- Proteins are COPOLYMERS of different amino acids
True or False: Thermosetting polymers are insoluble and infusible while thermoplastic polymers can be softened or melted by heat
True
True or False: Both methylcellulose and carboxymethylcellulose sodium are anionic in aqueous solution
False? (I don’t think methylcellulose is anionic but not 100% sure)
