Part 3 Flashcards
name the general components of aerosols
product concentrate + propellant
explain what the “product concentrate” of aerosols contains
it is a solution of:
-active ingredient
-antioxidants
-surface-active agents
-solvents
what does it mean if something has high vapor pressure
it is VOLATILE – meaning it evaporates easily
what are the most common liquefied gas propellants? are they used much anymore?
CFC (chlorofluoro carbons)
not used as much bc they destroy the ozone
if temperature is ____ than vapor pressure, the propellant becomes a gas
what does this mean about the vapor pressure of the propellants used in aerosols?
HIGHER
therefore, the propellants used in aerosols all have vapor pressures BELOW room temp (25 degrees celsius)
what is the concern with liquid density of propellants used in aerosols?
we want to know if their density is higher or lower than water
true or false
at room temperature, propellants are gasses
true
this is because they have vapor pressures that are lower than room temp
name the kinds of aerosol systems
-two phase systems
-three phase systems
-compressed gas systems
which are more popular - two phase aerosol systems or three phase systems?
two phase are more popular
explain the difference between the 3 aerosol systems
two phase systems = product concentrate + miscible liquid propellant + gas propellant
three phase system = liquid propellant that is NOT miscible with the product concentrate + gas propellant
compressed gas system = uses compressed gas (PSI)
name 3 types of containers used for aerosols
which is most popular?
glass (could be coated with plastic)
metal
plastics
metal is mot frequently used (aluminum - lightweight)
why are plastics not usually a suitable choice for aerosol containers?
not very good for maintaining pressure because it leaks out through pores from polymers
for which type of system must it be shaken before use?
3 phase system
explain the concept of three phase systems
the density of the immiscible liquid propellant is lower than the product concentrate so the liquid propellant remains on the top.
this means it won’t all get sprayed out. the only propellant that will get sprayed out is the very little bit that dissolves in the product concentrate
name 2 methods of filling aerosols
cold filling – both the product concentrate and propellant must be cooled. once returned to room temp, the liquid propellant will evaporate and create pressure (only in manufacturing)
pressure filling - can only be done in manufacturing. fit all liquid propellant back in under pressure when you run out
name 4 ways in which the filled aerosol containers are tested
leaking
valve assembly
particle size distribution
dose (for MDIs)
what serves as the reservoir to replenish the gas propellant
the liquid propellant. want to maintain equilibrium so when the bottle is sprayed and gas propellant leaves, some liquid evaporates to maintain equilibrium
name 4 major factors via aerosol inhalation
-physical factors (2 or 3 phase?)
-pattern of inhalation
-delivery device used (spacer)
-status of the lungs (what volume can the lungs hold? penetration/deposition?)
give an example of a dry powder inhaler.
SPINHALER turbo inhaler
true or false
SPINHALER turbo inhaler is a liquid aerosol that does not contain a canister
FALSE
solid aerosol. does not contain a canister
name an advantage of SPINHALER turbo inhaler
it’s a solid aerosol. therefore, we are not inhaling liquid propellant which is potentially bad for our bodies
generic for Intal
Cromolyn Sodium
name the dosage forms available for Intal
capsules (for inhalation)
nebulizer solution
metered dose inhaler
true or false
there are 3 Intal products available
true
capsules for inhalation
nebulizer solution
metered dose inhaler
what is the use of Intal
ANTIASTHMATIC
for prevention of exercise induced bronchospasms
define rheology
the study of flow. involves the viscosity characteristics of powders, fluids, and semisolids
name the types of flow
newtonian flow
non-newtonian flow
differentiate between the types of flow
Newtonian flow – CONSTANT VISCOSITY, regardless of the shear rates applies
non-newtonian flow - change in viscosity characteristics with increasing shear rates
non-newtonian flow includes…..
plastic, pseudoplastic, and dilatant flow
true or false
for non-newtonian flow, the viscosity can increase or decrease with increasing speed
TRUE
true or false
NEWTONIAN FLOW FOLLOWS NEWTONIAN’S LAW
true
define viscosity
an expression of the resistance to flow of a liquid system under an applied stress
what is “Poise”
the unit of viscosity.
the shearing force required to produce a velocity of 1cm/sec between 2 parallel planes of liquid
1cp =___poise
0.01 poise
explain what 1 centipoise is
1 centipoise = each 1 cm squared in area and separated by a distance of 1cm
give the USP/NF definition of Kinematic viscosity
the absolute viscosity divided by the density of the liquid AT A DEFINITE TEMPERATURE
what is the unit of kinematic viscosity
stoke
give the formula for kinematic viscosity
n’/p
p = density
n’ = absolute viscosity
at a constant _____, viscosity will NOT CHANGE
constant temperature
what is the simplest and cheapest method to measure viscosity ?
name the instrument
capillary viscometer
Ostwald viscometer
besides the capillary viscometer (Ostwald viscometer), name 4 other methods of measuring viscosity
falling sphere viscometer (Hoeppler viscometer)
cup and bob viscometer
cone and plate viscometer
brookfield viscometer
what is the absolute viscosity of water at 20 degrees celsius ?
1.0019 (assume 1)
name 6 newtonian liquids
castor oil
chloroform
ethyl alcohol
glycerin 93%
olive oil
water
rank the 6 newtonian liquids in order of increasing viscosity
highest - castor oil
glycerin (93%)
olive oil
ethyl alcohol
water
lowest - chloroform
what does the modified arrhenius equation measure
absolute viscosity using arrhenius constant, activation energy to intimate flow, gas constant, absolute temp
as the temperature of glycerin increases, what happens to viscosity
it decreases
explain what non newtonian flow is
change in viscosity = increasing shear rate
what are the types of non newtonian flow
plastic flow
pseudoplastic flow
dilatant flow
what pharmaceutical dosage forms are part of non newtonian flow?
colloidal solutions
emulsions
liquid suspensions
ointments
in plastic flow, what are the substances called?
Bingham bodies
explain plastic flow
does not begin until a shearing stress corresponding to a certain yield value (f) is exceeded
below (f), the materials are ELASTIC
in plastic flow, as viscosity _____ to a certain amount, shear rate remains relatively constant with further ___ in viscosity
decreases
in pseudoplastic flow, what are the substances called?
“shear-thinning” systems
what is the yield value in pseudoplastic flow
no yield value
in dilatant flow, what are the substances called?
shear thickening systems
in dilatant flow, what happens with increasing shear rate?
the volume of dilatant materials increases and the viscosity of them also increases
dilatant flow is the inverse of what flow?
pseudoplastic
besides plastic, pseudoplastic, and dilatant, name 3 other non newtonian flows
thixotropic
antithixotropic
rheoplastic
name 4 pharmaceutical areas in which rheology is significant
fluids
quasisolids (semisolids)
solids
processing
explain how the rheology of solids is a significant consideration in pharmaceutics
-the flow of powders from the hoppers and into the dye cavities in tablet/capsule during encapsulation
-packagability of powdered or granular solids
explain how “processing” rheology needs to be considered
-the production capacity of the equipment
-the processing efficiency
explain how the rheology of quasisolids (semisolids) needs to be considered
-spreading and adherence on the skin
-removal from jars or extrusion from tubes
-capacity of solids to mix wiht miscible liquids
-release of the drug from the base
explain how the rheology of fluids needs to be considered
-mixing
-particle size reduction of dispersed systems with shear
-passage through orifices (including pouring, packaging, and passage thorugh hypodermic needles)
-fluid transfer (inc pumping and flowing through pipes)
-physical stability of disperse systems
explain newtonians law of flow
force/amount of ointment = viscosity coefficient (n) * dv/dr
dv = difference in velocity
dr = difference of distance in dv
in Newtonian’s law of flow, what does it mean if dv is low?
the ointment is very viscous
what is F/A
force/area
represents shearing stress (F). given in newtonian’s law of flow
according to Newtonian’s law……..
the rate of shear should be directly proportional to the shearing stress
