Pulmonary Drug Delivery Flashcards
components of aerosols
propellant
container
valve
advantages of aerosols
alternative to parenteral fast onset of action direct systemic absorption noninvasive low dose minimal side effects tamper proof good stability accurate doses minimal potential for contamination
disadvantages of aerosols
local actions admin techniques patient compliance limited applications special drug properties unique production explosive and flammable environmental hazard high unit cost
basic requirements for aerosols
non or low irritability reasonable solubility low therapeutic activity physical/chemical compatibility satisfactory permeability pH range 5.5-7.5
respiratory diseases treated with aerosols
asthma
allergy
inflammation
COPD
drug types that use aerosols
corticosteroids
bronchodilators
non steroid antiinflammatory compounds
particle diameter 10um where will it deposit
oropharynx
particle diametes over 5 under 10um where will it deposit
central airways
particle diameter under 3 where wll it deposit
peripheral airways (gets to alveoli)
what is the systemic circulation
blood goes from left ventricle to the tissues to the right atrium
what is the pulmonary circulation
blood goes from right ventricle to lungs back to the left atrium
where is majority of absorption in the lungs
alveoli becuase thinner epithelium
some barriers of drug absorption in the central airway
mucus layer
cilia
epithelium
what are two places the drug is taken up in the central airway
blood vessel for systemic effects
smooth muscle for local action
barriers to drug absorption in the alveolus
surfactant
macrophage
epithelium
places of delivery in the alveolus
blood reaches systemic
endothelium for local action
epithelium for targeted delivery
bioavailability of aerosol compared to IV
slower absorption
more steady state
where is most of the inhaltion lost to
GI tract
5 things drug absorption depends on
particle size propellant valve admin techniques drug properties
what does the propellant do
push the drug out of the dosage form
3 types of propellents
chlorofluorocarbons
hydrofluorocarbons
hydrocarbons
what is the distribution of the contents of an aerosol when upright
vapour is lighter than the product so the porpellant sits at the top and product at the bottom
distribution of the inhlaer in the invert position
product at the bottom is in contact with the value
why do you want propellants with a low boiling point
become a gas at room temp so just drug goes in body
desired properties of CFC propellants
low toxicity nonflammable inert low boiling point, vapour pressure heavt density for MDIs only
why might you combine propellants
to play around with the boiling point and vapour pressure
desired properties for hydrocarbon propellants
nontoxic inert water based formulation low cost light density
advantage of hydrocarbons
environmentally acceptable
will new propellants be developed
no likely to develop new devices
is patient does not taste anything are they using it wrong
no might not get taste
what is a spray valve used for
topicals
what does a spray valve spray out
fine course spray or foam
is there a dose setting with a spray valve
no
what dies a metered dose valce spray out
fine spray or powder
metered dose vlaves have accurate doses in what range
50-75uL
why might there be diference in absorption with metered dose valves
patients admin technique
what are the coatings for on glass bottles
outside to protect from light and minimize breakage
inside to prevent interaction wth metals/glass
manufacturing of aerosols
spreacialized equipment and environment
complex processing
unique quality control procedures
more expensive
four things to test for quality control
drug content stays the same delivery rate and amount dose uniformity pressure testing water content total discharge numbers
how does an aerochamber work
slow down the aerosol so can slowly inhale and not lose to the environment
advantages of solution aerosols
fast action
lss irritability because small particles
easy formulas
disadvantages of solution aerosols
hard to find good cosolvent
stability issues
cosolvents in solution aerosols
ethanol
polyethylene/dipropylene glycol
ethyl acetate
acetone
contents of solution aerosols
drug in solution
fine particles
high portion of propellants
other additives
whats the first digit in propellat nomenclature
one less than the number of carbon atoms
whats the second digit of propellant nomenclature
one more than the number of hydrogen atoms
whats the 3rd digit of propellant nomenclature
number of fluorine atoms
advantages of suspension aerosols
fast onset
disadvantages of suspension aerosols
complex formulation
potential irritability
stability
size of particles in aerosols
5-10microns
why do you want low moisture with suspension aerosols
can cause aggregation
dispersion agents in suspension aerosols
polysorbates
sorbitan esters
oleyl alcohol
ethanol
what type of formulation comes from emulsion aerosols and for what use
foam for topical use
NOT FOR LUNGS
advantage and disadvantage of emulsion aerosol
easy to apply
stbaility issues
examples of emulsifiers
glyceryl monostearate
polyoxyethylene fatty esters
fatty acid esters
describe particle delivery with a propellant
spray out large droplets moving at a high velocity
propellant evaporate and fromation of small slow moving individual particles, aggregates, or partially evaporated droplets
describe particle delivery without propellants
drug bound to a carrier to make the particle size bigger then mesh screen breaks them apart releasing the drug from the carrier
spinhaler mechanism
perforating pins break open capsule to release drug
rotahaler mechanism
goes through a mesh
inhlator mechanism
pins puncture capsule, goes through grater and aerosolized
diskhaler mechanism
blister pack thing so multiple doses
easy haler mechanism
no propellant just push down to release the drug
propellant free advantages
safe
stable
compatible
environmentally friendly
propellant free disadvantages
formulation difficulty
extra procedures for admin
device care , use, adn storage
insert casule prior to use regular cleaning proper assemble keep away from children replace after 6 months
how to use metered dose inhalers
shake inhaler breathe out press the canister inhale deeply and slowly hold breathe for 10 seconds and exhale wait 30 seconds before next dose
extra step in the other inhalers
load the drug
future direction of inhalers
systemic
formulation modification and improvement
hardware invention
patient/consumer education
