Oral Drug Delivery Flashcards
What are 4 advantages of oral drug delivery?
1) Effectiveness - can produce sufficient systemic effects for tx outcomes. Result in satisfactory OoA, DoA, frequency of action
2) Accuracy - can provide accurate and safe drug doses while minimizing potential adverse effects/toxicities
3) Convenience - easy to handle and administer without invasiveness; contribute to improved patient compliance
4) Economy - large-scale industrial production reduces operational cost, reducing cost for patients. Solid dose forms are most stable chemically and physically (enhances shelf life)
What are 2 disadvantages of oral drug delivery?
1) Degradation/metabolism within GIT and by liver reduces overall drug distribution. Specific drug targeting is near impossible
2) Onset of action through this route might not be fast enough for emergency purposes. Not ideal for patients with dysphagia/vomiting. Special dosing needed for pediatric/geriatric patients. Drug interactions can occur in GIT, and irritation of absorption sites
Where are the two sites of absorption for oral drugs? which is the major site of absorption?
stomach
small intestine - major
what types of oral dosage forms are absorbed in the stomach?
tablet/capsules
solutions
suspension
some controlled release formulations
what factors influence the absorption in the stomach and small intestine?
pH
enzymes
food
liver metabolism
what types of oral dosage forms are absorbed in the small intestine?
EC tabs/caps
most controlled release formulations
drugs that were absorbed in the stomach will continue to be absorbed in the small intestine
what two sites in the GIT have limited drug absorption and why?
esophagus and colon
due to formulation profiles and biological functions of the sites
what are 3 necessary drug properties for oral drug administration and delivery?
1) reasonable absorption profiles - satisfactory aqueous solubility, able to cross membranes, low/no irritation at absorption site
2) Acceptable physical, chemical and biological stability - stability in environmental factors (temp, light, moisture, pH enzymes, first pass metabolism)
3) Good processing characteristics - active ingr. should exhibit compatibility with other pharmaceutical excipients, good compatibility and compressibility; handling
What are the 5 major obstacle in oral drug delivery?
solubility stability absorption metabolism drug targeting
how can drug solubility be increased?
selecting different drug salt forms
micronizing drug particles
improving formulation disintegration and dissolution
incorporating other additives such as surfactants
how can drug stability be improved? (in vitro)
coating
additive addition
packaging protection
controlled release formulations
what does coating do?
protects drug materials from degradation or interaction
how can controlled release formulation enhance drug stability?
reducing the amount of drug released into the environment
what are absorption profiles directly related to?
drug properties and the availability of drug compounds at the absorption site(s)
How can absorption be improved? (in vivo)
selecting appropriate active/inactive ingredients
increasing drug disintegration/dissolution rate
preventing drug compounds from decomposition
co-administering with/without food and/or water
what are the two groups of metabolism?
metabolism before absorption
metabolism after absorption
what are some ways to prevent drug metabolism before absorption?
structure modifications
coating
controlled release
what technique can achieve necessary drug concentrations in the blood after first pass metabolism?
concept of prodrugs
what other administration routes would be useful when hepatic metabolism is an issue?
rectal
sublingual
parenteral
what are some special drug delivery systems that can improve drug targeting?
microcapsules
liposomes
nanoparticles
what are two methods used to retain oral drugs in the stomach or small intestine?
hydrogels
polymers
Does oral dosing typically have a slow or fast onset? what does this mean in regards to duration of action?
fast onset
compromised duration - fast formulation disintegration and drug dissolution
What are some alternatives for pediatric/geriatric patients who can’t swallow solid oral dose forms?
liquid formulations
what is one advantage and disadvantage to oral solutions over solid oral dose form?
A - satisfactory outcomes regarding onset of action
D - duration of action may be shorter
what are some controlled release dosage forms?
tablets
capsules
injectables
transdermal patches
what is sustained release formulation?
any dosage form that provides medication over an extended period of time
what is controlled release formulation?
the system is able to provide some actual therapeutic control (controlling drug concentrations in the target site)
what characteristic makes an ideal controlled release formulation?
be able to provide an exact amount of drug at the site of action for a precise period of time
what are 5 unique characteristics of controlled release formulations?
1) enable patients to take less amount of drug with fewer administration frequencies (minimizes SE’s, drug accumulation)
2) enhance therapeutic outcomes by modifying drug release rate, reducing drug concentration fluctuations and improving drug bioavailability
3) patient compliance improved
4) average tx cost over time is less
5) quality control routines are more stringent and advanced
what is an appropriate half life for drug candidates?
2-8 hours
what is the downside to drugs with a short half life?
require excessively large amount of active ingredient in each dosage unit
what is the downside to drugs with a long half life?
not recommended for
