Oral Drug Delivery

Question 1

What are 4 advantages of oral drug delivery?

Answer 1

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)

Question 2

What are 2 disadvantages of oral drug delivery?

Answer 2

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

Question 3

Where are the two sites of absorption for oral drugs? which is the major site of absorption?

Answer 3

stomach

small intestine - major

Question 4

what types of oral dosage forms are absorbed in the stomach?

Answer 4

tablet/capsules
solutions
suspension
some controlled release formulations

Question 5

what factors influence the absorption in the stomach and small intestine?

Answer 5

pH
enzymes
food
liver metabolism

Question 6

what types of oral dosage forms are absorbed in the small intestine?

Answer 6

EC tabs/caps
most controlled release formulations
drugs that were absorbed in the stomach will continue to be absorbed in the small intestine

Question 7

what two sites in the GIT have limited drug absorption and why?

Answer 7

esophagus and colon

due to formulation profiles and biological functions of the sites

Question 8

what are 3 necessary drug properties for oral drug administration and delivery?

Answer 8

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

Question 9

What are the 5 major obstacle in oral drug delivery?

Answer 9

solubility
stability
absorption
metabolism
drug targeting

Question 10

how can drug solubility be increased?

Answer 10

selecting different drug salt forms
micronizing drug particles
improving formulation disintegration and dissolution
incorporating other additives such as surfactants

Question 11

how can drug stability be improved? (in vitro)

Answer 11

coating
additive addition
packaging protection
controlled release formulations

Question 12

what does coating do?

Answer 12

protects drug materials from degradation or interaction

Question 13

how can controlled release formulation enhance drug stability?

Answer 13

reducing the amount of drug released into the environment

Question 14

what are absorption profiles directly related to?

Answer 14

drug properties and the availability of drug compounds at the absorption site(s)

Question 15

How can absorption be improved? (in vivo)

Answer 15

selecting appropriate active/inactive ingredients
increasing drug disintegration/dissolution rate
preventing drug compounds from decomposition
co-administering with/without food and/or water

Question 16

what are the two groups of metabolism?

Answer 16

metabolism before absorption

metabolism after absorption

Question 17

what are some ways to prevent drug metabolism before absorption?

Answer 17

structure modifications
coating
controlled release

Question 18

what technique can achieve necessary drug concentrations in the blood after first pass metabolism?

Answer 18

concept of prodrugs

Question 19

what other administration routes would be useful when hepatic metabolism is an issue?

Answer 19

rectal
sublingual
parenteral

Question 20

what are some special drug delivery systems that can improve drug targeting?

Answer 20

microcapsules
liposomes
nanoparticles

Question 21

what are two methods used to retain oral drugs in the stomach or small intestine?

Answer 21

hydrogels

polymers

Question 22

Does oral dosing typically have a slow or fast onset? what does this mean in regards to duration of action?

Answer 22

fast onset

compromised duration - fast formulation disintegration and drug dissolution

Question 23

What are some alternatives for pediatric/geriatric patients who can’t swallow solid oral dose forms?

Answer 23

liquid formulations

Question 24

what is one advantage and disadvantage to oral solutions over solid oral dose form?

Answer 24

A - satisfactory outcomes regarding onset of action

D - duration of action may be shorter

Question 25

what are some controlled release dosage forms?

Answer 25

tablets
capsules
injectables
transdermal patches

Question 26

what is sustained release formulation?

Answer 26

any dosage form that provides medication over an extended period of time

Question 27

what is controlled release formulation?

Answer 27

the system is able to provide some actual therapeutic control (controlling drug concentrations in the target site)

Question 28

what characteristic makes an ideal controlled release formulation?

Answer 28

be able to provide an exact amount of drug at the site of action for a precise period of time

Question 29

what are 5 unique characteristics of controlled release formulations?

Answer 29

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

Question 30

what is an appropriate half life for drug candidates?

Answer 30

2-8 hours

Question 31

what is the downside to drugs with a short half life?

Answer 31

require excessively large amount of active ingredient in each dosage unit

Question 32

what is the downside to drugs with a long half life?

Answer 32

not recommended for