PHA 317 Exam 2 Interfacial
Phenomena Questions and
Answers 100% Pass
adsorption - CORRECT ANSWER-primarily a surface phenomenon
absorption - CORRECT ANSWER-occurs throughout th entire bulk of a
substance
surface active agents, surfactants, or amphiphies - CORRECT ANSWER-
molecules that can be adsorbed and reduce surface tension.
what must be present on a molecule for it surface to have activity? - CORRECT
ANSWER-the molecule must be hydrophilic group (facing the bulk) and lipophilic
group (facing the air)
micelles - CORRECT ANSWER-clusters of molecules in the bulk of the solution.
these are formed when the surface and of liquid is fully saturated. this minimize
interfacial energy
monomers - CORRECT ANSWER-individual molecules on the surface of the
liquid
, how can micelles solubilize lipophilic drugs? - CORRECT ANSWER-the interior
of a micelle is lipophilic (assuming molecules are in a aqueous solution), this
lipophilic center can trap lipophilic drugs and because like dissolves like the drug
can solubilize
critical micellar concentration (CMC) - CORRECT ANSWER-The concentration
above which the monomers of surfactant start associating to form micelles
CMC and water properties - CORRECT ANSWER-before CMC is reached
surface properties of the liquid (surface and interfacial tension, vapor pressure) are
affected. after CMC is reached bulk properties of the liquid (density, conductivity)
are affected.
how can you use micelles to suspensions and emulsions? - CORRECT ANSWER-
lipophilic core of micelles can be used to solubilize drug molecules in solutions and
suspensions. The core can also be used to solubilize droplets of oil that is
ordinarily immiscible in water.
HLB (hydrophile-lipophile balance) - CORRECT ANSWER-a measurement tool
for surface activity. The higher the HLB of an agent, the more hydrophilic it is.
According to this classification, Spans, or sorbitan esters, have low HLB values of
1.8 to 8.6, whereas Tweens, or polyoxyethylene derivatives of spans, are
hydrophilic and have high HLB values of 9.6 to 16.7.
Phenomena Questions and
Answers 100% Pass
adsorption - CORRECT ANSWER-primarily a surface phenomenon
absorption - CORRECT ANSWER-occurs throughout th entire bulk of a
substance
surface active agents, surfactants, or amphiphies - CORRECT ANSWER-
molecules that can be adsorbed and reduce surface tension.
what must be present on a molecule for it surface to have activity? - CORRECT
ANSWER-the molecule must be hydrophilic group (facing the bulk) and lipophilic
group (facing the air)
micelles - CORRECT ANSWER-clusters of molecules in the bulk of the solution.
these are formed when the surface and of liquid is fully saturated. this minimize
interfacial energy
monomers - CORRECT ANSWER-individual molecules on the surface of the
liquid
, how can micelles solubilize lipophilic drugs? - CORRECT ANSWER-the interior
of a micelle is lipophilic (assuming molecules are in a aqueous solution), this
lipophilic center can trap lipophilic drugs and because like dissolves like the drug
can solubilize
critical micellar concentration (CMC) - CORRECT ANSWER-The concentration
above which the monomers of surfactant start associating to form micelles
CMC and water properties - CORRECT ANSWER-before CMC is reached
surface properties of the liquid (surface and interfacial tension, vapor pressure) are
affected. after CMC is reached bulk properties of the liquid (density, conductivity)
are affected.
how can you use micelles to suspensions and emulsions? - CORRECT ANSWER-
lipophilic core of micelles can be used to solubilize drug molecules in solutions and
suspensions. The core can also be used to solubilize droplets of oil that is
ordinarily immiscible in water.
HLB (hydrophile-lipophile balance) - CORRECT ANSWER-a measurement tool
for surface activity. The higher the HLB of an agent, the more hydrophilic it is.
According to this classification, Spans, or sorbitan esters, have low HLB values of
1.8 to 8.6, whereas Tweens, or polyoxyethylene derivatives of spans, are
hydrophilic and have high HLB values of 9.6 to 16.7.
