Drug delivery system Flashcards
What three factors determine the drug delivery system we use
The dose of the drug to be given
The frequency of administration
The timing of administration
What is a prodrug
synthesised inactive derivatives of an active drug metabolically activated after administration
What is the advantages of a prodrug
prolongation of action
What are methods of drug delivery
Oral Sublingual suppositories pessaries IV Intramuscular Transdermal - patches, percutaneous Inhalation carrier based drug delivery therapy
What is the benefit of oral suspension
dosage contained with small volume
insoluble
insoluble unpalatable drugs are better tolerated
rapid, especially in small intestine
What is the rate limiting step in absorption of oral tablets
dissolution
What does modified release tablet do
reduces rate of absorption allowing a slow but sustained release over a long period of time
Why is modified release useful
for disorders requiring prolonged therapy
maintaining drug levels within therapeutic range
reduces the need for frequenting dosing
improves compliance
What is the purpose of enteric coated tablets
delays disintegration until tablet reaches the small intestine
What is the two benefits of enteric coated tablets
Protects the stomach from the drug
protects the drug from the stomach
Example of a drug that can cause damage to the stomach
aspirin
Why is omeprazole enteric coated
to protect it from stomach acid
Where is oral tablets absorbed via
small intestine
What is the advantages of sublingual
bypasses first pass metabolism
small and dissolve under the tongue going straight into circulation
What route do suppositories follow
rectal
What are the advantages of suppositories
by pass first pass metabolism
useful for patients who cant swallow, young or old
treats local conditions
What is a pessaries is used to treat
thrush
What are the benefits of injection based delivery
fast systemic effect
bypass first pass metabolism
can administrate to unconscious patients
short half life therefore can continuously infuse
What are three types of injection based delivery
IV - into viens
IntraMuscular - into muscle
Subcutaneously - applied under the skin
Why is it beneficial that IV allows continually infusion
allows accurate control with narrow therapeutic index
How do you prevent toxicity of IV delivery
deliver it slowly
What is an disadvantage intramuscular
may be painful
example of intramuscular injection
Contraceptive
What are two different types of subcutaneous injections
Dermojet - needless injection used for mass inoculation
Pellet implantation - solid pellet implantation
