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PHCY 512 - Exam 2 Questions with Correct Answers
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PHCY 512 - Exam 2 Questions with Correct Answers
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PHCY 512 - Exam 2 Questions with Correct AnswersSurface tension is between ___ and ______ Correct Answer-air and
liquid
Interfacial tension is between ______ ______ ______ Correct Answer-
two immiscible liquids
These accumulate at the boundary between two phases, resulting in
reduction of interfacial tension Correct Answer-Amphipathic
compounds
Oil liking Correct Answer-Lipophilic
water liking Correct Answer-hydrophilic
liking both water and oil Correct Answer-amphiphilic
Combining natures of water an oil Correct Answer-amphipathic
affinity for solvent Correct Answer-lyophilic
lack of affinity for solvent Correct Answer-lyophobic
,Surfactants with a negatively charged head group. Includes Alkane
carboxylate salts, sulfates, and alkyl/aryl sulfonates. Correct Answer-
Anionic
Surfactants with positively charged head group. Includes long-chain
amines and quaternary ammonium salts Correct Answer-Cationic
Surfactant with overall neutral charge. Makes up most biological
membranes in a bilayer. Correct Answer-Zwitterionic
Surfactant with 4 hydroxyl groups that can be substituted and no
charges. Correct Answer-Non-ionic
At low surfactant concentrations, how do surfactant molecules align at
the air-liquid interface? Correct Answer-polar (hydrophilic) head in
water, non-polar (hydrophobic) tails toward air.
The point where the air-liquid interface is saturated and further addition
of surfactant causes micelles to form. The concentration of surfactant
molecules in solution does not change as additional surfactant is added.
Correct Answer-Critical Micelle Concentration (CMC)
True or false: Micelles are used to solubilize poorly soluble drugs.
Correct Answer-True - micelles can be used to increase the apparent
aqueous solubility of lipophilic drugs.
,O/W emulsions represent ____ in ___ while W/O is ____ in _____
Correct Answer-O/W = Oil in water
W/O = Water in oil
A physical/chemical classification system for lipids, surfactants, and
emulsifying agents. Represents the ratio of hydrophilic to lipophilic.
Correct Answer-Hydrophilic-lipophilic balance (HLB)
As the HLB number increases, surfactants become more _______
Correct Answer-hydrophilic
Adding polyoxy groups greatly ____ the HLB Correct Answer-increases
Decreasing the number of fatty acid groups _____ the HLB Correct
Answer-increases
A longer hydrophobic group _____ the surfactant's lipophilicity, and
causes micelles to form at a _____ concentration. (think adding more
carbons to tail) Correct Answer-increases lipophilicity; lower
concentration
A longer/larger hydrophilic group _____ the hydrophilicity of the
surfactant and causes the micelles to form at a ____ concentration
Correct Answer-increases hydrophilicity; higher concentration.
, Non-ionic micelles have____ CMC than ionic micelles. Correct Answer-
Lower
A weakly hydrated counterion will form a [larger/smaller] micelle.
Correct Answer-larger.
True or False: It is appropriate to dilute micellar drug products prior to
administration. Correct Answer-False- this will change the concentration
and cause the drug to crash out.
A mixture of oil, non-ionic surfactant, and drug (and possibly other
components) which forms a fine emulsion in the aqueous lumen of the
gut. They are low in water content allowing for encapsulation of a unit
dose. Forms microemulsion upon dilution in GI tract. Correct Answer-
self-emulsifying drug delivery system (SEDDS)
The separation of proteins into hydrophilic and hydrophobic regions
(like a surfactant) that causes the protein to lose its ability to function.
This may be followed by aggregation. Correct Answer-Denaturation of
proteins
The surfactants in our bodies are found in the GI tract, our eyes, and in
our lungs. They are... Correct Answer-bile salts (GI), Surfactant Protein-
A (eyes), and Pulmonary surfactant (lungs)
This emulsifies fats and oils into smaller droplets for subsequent
enzymatic degredation Correct Answer-bile salts
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