Part 2 Flashcards
if we need to reduce the size of the particles, what kind of agent do we use?
if the particle size does NOT need to be reduced, what kind of agent do we use?
particle size doesnt need to be reduced = wetting agent
needs to be reduced = levigating agent
name 2 things that affect the bioavailability of drugs from suspensions
-dispersed powder
-dispersed vehicles
name 4 ways in which the dispersed powder affects the bioavailability of drugs from suspensions
-particle size
-particle shape
-surface characteristics
-polymorphism
how can the dispersed vehicle affect the bioavailability
if the medium is too viscous, the powder will diffuse very slowly out of the medium.
therefore, we don’t want the viscosity too high - only 1-2% methylcellulose
true or false
a suspension with smooth surface particles will have higher bioavailability than rough surface particles
FALSE
rough particles will have higher bioavailability bc dissolution rate is higher
at the oil-water interface (in the cause of suspensions - particle - water interface), what exists?
an electrical double layer
what is “e”
energy potential on the particle surface. represents the energy that comes from the surfactant itself
(we don’t really measure this – we measure zeta)
what can you say about the charge of the bulk solution in a suspension
it is electrically NEUTRAL
at a position very close to a solid particle in a suspension, is the zeta potential high or low?
very high. as you move further away from the particle and approach the bulk solution, the zeta potential decreases exponentially
2 particles are very far away from each other. as 1 particle approaches the other, does the zeta potential increase or decrease?
increase
particles with a very large contact angle are hydrophobic or hydrophilic
hydrophobic
the function of a wetting agent is to get rid of the air above the solid particles.
how is this helpful in a suspension?
helps the particles disperse in the medium
true or false
if a wetting agent is used, a levigating agent is not needed
true
zeta potential measures what part of a suspension
the mobile or diffuse portion of the double layer
(Fixed layer = around the solid particle)
define gels
gels are semisolid systems consisting of either –
-suspensions made of inorganic particles
-large organic molecules
interpenetrated by a liquid
name 4 advantages of gels
-semisolid
-easy to apply and remove
-high degree of clarity
-compared to ointments and creams, they have fast release of drug
which have faster release of drug – ointments/creams or gels?
gels have faster drug release
give an example of a gel and explain it in detail
Aluminum Hydroxide Gel, USP (BASIC)
it is an aqueous suspension of gelatinous precipitate (made of insoluble aluminum hydroxide and hydrated aluminum hydroxide, equivalent to about 4% aluminum oxide
neutralizes a portion of gastric HCl and is used to treat hyperacidity and peptic ulcers.
-this will remain in the stomach for local effects while a tablet would go to the small intestine
true or false
Aluminum Hydroxide, USP is an acidic drug
FALSE - basic. that’s how it can neutralize stomach acid
how can gels be classified
4 types:
-inorganic
-organic
-hydrogels
-organogels
true or false
inorganic gels are typically single-phase systems and organic gels are typically two-phase sytems
FALSE
inorganic gels are typically 2-phase
organic gels are typically single-phase
give 2 examples of inorganic gels
aluminum hydroxide gel
bentonite magma
gave 2 examples of organic gels
carbopol
tragacanth
explain what Carbopol is
frequently used in research
an organic, single phase system.
USED TO INCREASE THE VISCOSITY OF THE DISPERSED MEDIUM. the drug will dissolve in the water and then that water will integrate into the Carbopol structure
TRUE OR FALSE
tragacanth forms an inorganic gel
false - organic
name 3 classes of hydrogels
-organic hydrogels
-natural and synthetic gums
-inorganic hydrogels
give 2 examples of organic hydrogels
pectin paste, tragacanth jelly
give 3 examples of natural and synthetic gums.
what class of gel do they form?
methylcellulose, sodium carboxy methylcellulose, Pluronic
hydrogels
give 3 examples of inorganic hydrogels
bentonite gel (10-25%)
veegum
silica
name 6 types of organogels
hydrocarbon type
animal, vegetable fats
soap base greases
hydrophilic organogels
polar
nonionic
give 2 examples of hydrocarbon type organogels
petrolatum
mineral oil/polyethylene gel (Plastibase)
what is Plastibase
a hydrocarbon type organogel made of mineral oil/polyethylene gel
give 2 examples of organogels that are made of animal/vegetable fats
lard, cocoa butter
give an example of soap base greases that is an organogel
aluminum stearate with mineral oil gel
carbowax bases form what kind of gel?
hydrophilic organogels
(PEG ointment)
carbowax ointment =…..
PEG ointment (hydrophilic organogel)
which type of gel has a high concentration of suspending agent?
hydrogels
what do gelling agents do?
when placed into water, they will form a gel
“bases of this class include organic and inorganic ingredients that are colloidally dispersable or soluble in water”
hydrogels
true or false
magmas do not need a suspending agent
TRUE
define magmas
an aqueous suspension of insoluble inorganic drugs. thick and viscous and does NOT need a suspending agent
explain how magmas are prepared
by freshly precipitating the dispersed phase in order to achieve a fine degree of subdivision of the particles and a gelatinous character (viscous) to those particles.
relies on the swelling properties of the excipients. takes ~24 hours.
can use a mixer to speed up, but there’s not enough time for it to swell. acceptable, but not as acceptable
give 2 examples of magmas
bentonite magma, NF
milk of magnesia
explain what Bentonite Magma, NF is and what it’s used for
a preparation of 5% bentonite, a native colloidal hydrated aluminum silicate, in purified water
it is used as a suspending agent and vehicle for drug
it is a magma
explain what milk of magnesia is and what it’s used for
a preparation containing magnesium hydroxide (base)
a dose of 5mL will neutralize ~10mEq of stomach acid
stored in a TIGHT CONTAINER 0-35 degrees celsius
like Aluminum Hydroxide Gel - it will remain in the stomach for a long time
what is a side effect from taking too much milk of magnesia?
too much magnesium hydroxide will cause diarrhea
rank the following according to viscosity:
-gel
-suspension
-magma
least viscous = suspension
middle = gel
most viscous = magma
what is a side effect from too much aluminum hydroxide
constipation
since the side effect of excess aluminum hydroxide is constipation and too much magnesium hydroxide is diarrhea, what is the solution to this?
a mixture of the 2 to neutralize stomach acid to lessen any potential side effects
true or false
lotions can be used both orally and topically
FALSE – only topical
give the definition of lotions
either liquid or semisolid preparations which contain 1 or more active ingredients in an appropriate vehicle(s)
they are usually suspensions of finely divided solids in an aqueous medium – but the particles should be so small that we can’t see or feel them
explain how lotions are intended to be applied
to unbroken skin without friction
name the types of excipients that are included in lotions
-dispersing agent
-cooling agent
-protecting and hydrating agent
as mentioned, the excipients included in lotions are a dispersing agent, cooling agent, and a protecting/hydrating agent
give examples of each
dispersing agent = bentonite, methylcellulose
cooling agent = alcohol
protecting/hydrating agent = glycerin
solid particles require ___ to be dispersed in the dispersion medium
if LIQUID, _____ needed to be dispersed
explain how this applies to lotions
wetting agent
if liquid, needs emulsifying agent
since lotions can be liquid in liquid OR solid in liquid, we just term it as needing a “dispersing agent”
true or false
bentonite magma can be used as a suspending agent in lotions
true
explain how glycerin works in a lotion
as a protecting and hydrating agent.
keeps the moisture in the product (humectant) AND on the skin, since the alcohol included in the lotion (for cooling effect) will extract the water out of the skin
give an example of a commercially available lotion
calamine lotion
when applying a lotion, you feel grittiness on your skin.
this indicates an error with the addition of which agent?
wetting agent.
function of wetting agent is to keep the particle size very small, and if roughness is being felt the size is not as small as it should be
give the definition of pharmaceutical aerosols
a pressurized dosage form containing 1 or more active ingredients which upon actuation emits a fine dispersion of liquid and/or solid materials in a gaseous medium
in aerosols, what is the dispersed phase and what is the medium?
the dispersed phase can either be fine liquid or fine solid
the dispersed medium is GAS
how many types of pharmaceutical aerosols are there?
name them
-inhalation
-nasal
-lingual
-topical
-vaginal and rectal
which type of aerosol contains MDIs?
(METERED DOSE INHALERS)
inhalation aerosols
of the types of inhalation aerosols, which has a similar onset time to IV
lingual aerosols
name 5 major advantages of pharmaceutical aerosols
easily withdrawn without contamination
protection of medicinal agents
no touching the affected area
controlled dosing
clean application
explain how being “easily withdrawn without contamination” is an advantage of pharmaceutical aerosols
we touch capsules/tablets, but we dont touch the mist that comes from an aerosol
explain how “protection of medicinal agents” is a major advantage of pharmaceutical aerosols
the entire aerosol dosage form is sealed from the environment
true or false
a major disadvantage of the aerosol dosage form is that there are more in number and more severe side effects than the oral or parenteral routes
FALSE
there are fewer and less severe side effects for the aerosol dosage form than for oral and parenteral, and this is an advantage for the aerosol dosage form
name 2 disadvantages of the aerosol dosage form
-difficulties in dosage estimation and reproducibility
-difficulties in coordinating hand action and breathing with MDIs
explain the proper storage and administration of pharmaceutical aerosols
store between 15-30 degrees celsius (59-86 degrees F)
shake before use, hold at the proper angle and/or distance from the target
explain temperature limitations of pharmaceutical aerosols
it cannot be stored at very high temperatures. this will cause a buildup of pressure and could cause explosion
why do pharmaceutical aerosols need to be shaken before use?
there are 2 systems contained in an aerosol.
thus, we want to shake before use to determine homogeneity between the phases
where is the usual site of action for the aerosol dosage form? what advantage follows with this?
the usual site of action is LOCAL (the lungs)
therefore, an advantage of the aerosol dosage form is that it requires smaller doses than for those dosage forms that require systemic treatment.
there is no absorption mechnism
true or false
for the aerosol dosage form, there is rapid onset of drug action
TRUE
this is because the drug is at the usual site of action (lungs) right away
the aerosol dosage form has targeted delivery to ______
respiratory
true or false
the aerosol dosage form is painless and relatively convenient
true
what particular feature of the metered dose inhaler keeps the dose constant?
the metering valve
solid in solid
paste
solid in liquid
magma
suspension
lotion
solid in gas
solid aerosols (smoke, dust)
liquid in solid
absorption bases, emulsion bases, butter
liquid in liquid
emulsion
lotion
liquid in gas
liquid aerosols -
mist, fog, nasal sprays
gas in solid
solid foams
gas in gas
NO COLLOIDAL DISPERSIONS
gas in liquid
foams, carbonated beverages
what are the 2 “key words” for aerosol delivery?
penetration and deposition
true or false
stability is a concern for every dosage form
true
name 4 classes of drugs for the aerosol dosage form
bronchodilators
decongestants
mucus-controlling
anti-inflammatory
for penetration into the DEEP LUNGS, what must the size range of the droplets/particles be?
1-5 micrometers
for the upper lungs, what size of the droplets/particles is needed for penetration?
5-10 micrometers
in the NOSE any particle/droplet greater than __ is removed
in the MOUTH, any particle/droplet greater than ____ is removed
nose - anything greater than 10 micrometers
mouth - anything greater than 15 micrometers
true or false
particle size is related to deposition
FALSE – penetration
which has longer duration and why - solid aerosols or liquid aerosols?
solid aerosols have longer duration because they have better deposition and aren’t removed when we breathe in and out.
they are deposited and slowly dissolved and thus have a longer duration of action
we want most drugs to have an effect in the upper or deep lungs? what does this mean?
deep lungs
therefore, particle size must be 1-5 micrometers (last 5-6 gen)
for upper lungs = 5-10 micrometers (1st 6 generations)
what is intal
an aerosol containing lactose (30-60 micrometers) and cromolyn sodium (2-6 micrometers)
