PHA 317: Pharmaceutics I Exam 2
UPDATED Questions and CORRECT
Answers
Rheology - CORRECT ANSWER - The science that studies the flow of liquids and
deformation of solids
biological availability - CORRECT ANSWER - The rheology of a particular product can
affect its patient acceptability, physical stability, and even __________ _____________
Viscosity - CORRECT ANSWER - ___________ is the resistance offered by a liquid or a
fluid to flow - denoted by the symbol n
Fluidity - CORRECT ANSWER - __________ is the ease with which a liquid or a fluid
flows, and is defined as the reciprocal of viscosity
paste and ointment - CORRECT ANSWER - Water for injection is a Newtonian fluid, but
zinc oxide _______ & ___________ are examples of non-Newtonian fluids
Newtonian Fluids - CORRECT ANSWER - The force, F, applied per unit area is
proportional to Vg and is a straight line in the plots
poise - CORRECT ANSWER - The unit of viscosity is the __________ (units are g/cm
sec)
Kinematic viscosity - CORRECT ANSWER - Equal to viscosity normalized to its density
at a particular temperature (units are stoke(s) or centistokes (cS)
increases - CORRECT ANSWER - Viscosity of a gas ________ with temperature, for
liquids , it decreases with temperature
, Plastic Flow - CORRECT ANSWER - Does not flow until the applied shearing stress
exceeds minimal value (called yield value) - below the yield value, material behaves as an elastic
solid and above yield value as a Newtonian liquid - generally by CONCENTRATED
SUSPENSIONS
Pseudoplastic Flow - CORRECT ANSWER - Flows more readily with increased shearing
stress - such liquids become thinner on the application of stress, polymers in SOLUTION
generally exhibit this type of flow
Dilatant Flow - CORRECT ANSWER - Liquids become thicker, or flow with increased
resistance with application of stress (opposite of pseudoplastic) - generally exhibited by
CONCENTRATED SUSPENSIONS (>50% W/V)
Thixotropic Flow - CORRECT ANSWER - Special characteristic exhibited by shear
thinning systems, such as pseudoplastic and plastic liquids - when shear is applied to these
materials, the resistance to flow progressively decreases - if shear is removed, they remain in
"thinned state" - useful for many PHARMACEUTICAL PREPARATIONS
constant - CORRECT ANSWER - Those that operate at a single rate of shear are useful
for Newtonian liquids because the viscosity is a ___________ function of the rate of shear
Capillary viscometers - CORRECT ANSWER - _________ __________ such as the
Ostwald viscometer are useful for liquids that flow relatively easily because the measurement is
based on flow through capillary tube
multiple - CORRECT ANSWER - Those that operate at _____________ rates of shear are
useful for Non-newtonian fluids and may also be used for semisolid substances such as gels and
pastes - examples include cup & bob viscometer and the cone & plate viscometer
Blood - CORRECT ANSWER - ________ is fluidized suspension of elastic cells whose
flow is regulated by viscoelastic properties
UPDATED Questions and CORRECT
Answers
Rheology - CORRECT ANSWER - The science that studies the flow of liquids and
deformation of solids
biological availability - CORRECT ANSWER - The rheology of a particular product can
affect its patient acceptability, physical stability, and even __________ _____________
Viscosity - CORRECT ANSWER - ___________ is the resistance offered by a liquid or a
fluid to flow - denoted by the symbol n
Fluidity - CORRECT ANSWER - __________ is the ease with which a liquid or a fluid
flows, and is defined as the reciprocal of viscosity
paste and ointment - CORRECT ANSWER - Water for injection is a Newtonian fluid, but
zinc oxide _______ & ___________ are examples of non-Newtonian fluids
Newtonian Fluids - CORRECT ANSWER - The force, F, applied per unit area is
proportional to Vg and is a straight line in the plots
poise - CORRECT ANSWER - The unit of viscosity is the __________ (units are g/cm
sec)
Kinematic viscosity - CORRECT ANSWER - Equal to viscosity normalized to its density
at a particular temperature (units are stoke(s) or centistokes (cS)
increases - CORRECT ANSWER - Viscosity of a gas ________ with temperature, for
liquids , it decreases with temperature
, Plastic Flow - CORRECT ANSWER - Does not flow until the applied shearing stress
exceeds minimal value (called yield value) - below the yield value, material behaves as an elastic
solid and above yield value as a Newtonian liquid - generally by CONCENTRATED
SUSPENSIONS
Pseudoplastic Flow - CORRECT ANSWER - Flows more readily with increased shearing
stress - such liquids become thinner on the application of stress, polymers in SOLUTION
generally exhibit this type of flow
Dilatant Flow - CORRECT ANSWER - Liquids become thicker, or flow with increased
resistance with application of stress (opposite of pseudoplastic) - generally exhibited by
CONCENTRATED SUSPENSIONS (>50% W/V)
Thixotropic Flow - CORRECT ANSWER - Special characteristic exhibited by shear
thinning systems, such as pseudoplastic and plastic liquids - when shear is applied to these
materials, the resistance to flow progressively decreases - if shear is removed, they remain in
"thinned state" - useful for many PHARMACEUTICAL PREPARATIONS
constant - CORRECT ANSWER - Those that operate at a single rate of shear are useful
for Newtonian liquids because the viscosity is a ___________ function of the rate of shear
Capillary viscometers - CORRECT ANSWER - _________ __________ such as the
Ostwald viscometer are useful for liquids that flow relatively easily because the measurement is
based on flow through capillary tube
multiple - CORRECT ANSWER - Those that operate at _____________ rates of shear are
useful for Non-newtonian fluids and may also be used for semisolid substances such as gels and
pastes - examples include cup & bob viscometer and the cone & plate viscometer
Blood - CORRECT ANSWER - ________ is fluidized suspension of elastic cells whose
flow is regulated by viscoelastic properties
