exam 3 munson Flashcards
routes of admin of dosage forms
oral - 47%
parenteral (subcutaneous, IM, IV) - 18%
pulmonary - 16%
transdermal - 11%
other - 8%
dosage form
route of admin dictates dosage form - oral is most common since it is most stable and easiest
tabs + caps
stable
accurate dose
easy to use
low costs
additional functions like CR + ER
not for kids/infants
not for non oral meds
IV
fast acting
for those who cant tolerate GI environments
for those who can swallow
expensive
not convenient bc requires help
pain
transdermal patches
mostly for local treatment
intranasal spray
mostly local treatment
can also be used for systemic drug delivery
solid dosage forms
tabs, gelcaps, loose powders, lyophilized powders, controlled release
types of tabs
compressed, film coated, enteric coated, multiple compressed, layered, chewable, tablets for solution, effervescent, dispensing
Why tabs?
stability, simplicity, portability, compactness, ease, shape, size + weight, compressed + molded
Compressed tabs
can have coating or not, formed by compression
sugar coated tabs
formed by compression, used for taste masking/identification
enhance stability from oxidation
film coated tabs
adds 2-6% weight
can avoid use of moisture
can put markings on tabs
compressed layer tablets
multiple comrpession: typically have inner core and coating, inner can be sugar tab
multiple layer:
lightly compress one layer, additional layer added
enteric coated tab
resists dissolving in the stomach it dissolves at basic pH. cannot crush or chew
chewable tab
designed to be chewed, may help with solubility, may not need water, avoids problems w/ swallowing. example singulair
effervescent tab
dissolved in glass of water prior to admin
releases CO2
facilitates fast action
hard gel cap
used in most capsules
commonly employed for clinical trials
made of collagen
might snap together or heat sealed
soft gel cap
used for liquids, suspensions, pastes, solids
uses two ribbons may have diff colors
solid state vs solution
solution: faster acting, less stable, more parenteral admin
solid state: slower to act bc must get into solution, more stable, more convienet
drug substance to dosage form
preformulation: physicochemical properties of the drug
formulation: determining route and composition of final dosage form
solution
preformulation: solubility and stability
solubility: equilibrium state, max amount of solute that can be dissolved in given amount of solvent
3 states: completely soluble, supersaturated, very supersaturated
physical + chemical stability
solids are very stable
most reactions start at crystal defects
types of reactions: hydrolysis, oxidation, photolysis, dehydration
excipients
role: preservative, solubility enhancer, stability enhancer, taste masking
types: diluents, disintegrants, binders, lubricants, glidants, controlled release
diluents
bulking agents, used to make practical weight for tablet
disintegrants
breaks up solid dosage form, enhances dissolution
binders
gives mechanical strength
lubricants
prevents adherence after compaction
glidants
improves powder flow
formulating dosage forms
physical and chemical properties
mechanical properties
biopharmaceutical properties
physical and chemical properties
aqeuos solubility
dissolution rate
ionization constant
polymorphism
amorphous
hydroscopicity
mechanical properties
compression and compaction
manufacturing tab
taking API and turning it into dosage that is stable, soluble, and easy to administer
tab manufacturing steps
mixer
granulation
drying
particle size reduction
additional mixing
tabletting
modified release
release where time course, location, or both are altered for therapeutic effect
delayed release applications
avoid release in the stomach: by pass acidic environment, minimize stomach irritation
chronotherapy: timing drug release to be in harmony w/ bio rhythm
stratgey to avoid stomach pH
change drug pH
avoid dissolution in the stomach (enteric coated tablets)
polymers employed for enteric coatings
pthalate contains one free ionizable COOH group that increases pH values
why is release responsive to pH
polymer remains tightly packed at pH 1-2 in stomach
polymer ionizes at pH 5-6 in small intestine
extended release system
slowly releases drug over period of time
greater dose less frequent has higher peaks, but lower lows.
zero order release stays in therapeutic range longer
diffusion systems
release of drug is determined by diffusion through a poorly water-soluble polymer
reservoir device
core of drug is surrounded by poorly water soluble polymeric membrane
zero order release
matrix device
not zero order release
drug is mixed with a polymer and compressed/dispersed in molten wax which is then cooled to solidify
this slows down initial release
flux from matrix systems
rate of release (flux) is not constant with time
it levels out
oxycontin
controlled release
two absorption half-lives every 12 h for pain
chewing these ruin the controlled delivery mechanism
