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
Example of dermojet and pellet implantation
Insulin
testosterone
How is the drug absorbed in transdermal
diffuses by skin absorption
What are the different from of transdermal
adhesive patch
percutaneous - creams/ointments
What is the advantage of transdermal
By pass first pass metabolism
controlled level of drugs
Example of transdermal adhesive patches
HRT
Contraception
Nicotine
Opiates
What is an example of a local and systemic percutaneous
local - steroid
systemic - HRT
What is the advantages of inhalation
delivered directly to the lungs
rapid
little systemic absorption
reduced adverse reactions
What are different methods of carrier based drug delivery
monoclomal antibodies
Liposomal drug delivery
Nanoparticle based drug delivery
Genetic transfer system
What is the purpose of monoclonal antibodies
bind to cancer specific antigen and induce immune response to cancer cells
what is the advantaged of Liposomal drug delivery
reduced toxicity
enhanced efficiency
What is the advantage of nanotechnology
target precise location
therefore: more effective, specific
Reduce toxicity
what are nanoerythrosomes
resealed erythrocytes that carry proteins, enzymes and macromolecules
what can nanoerythrosomes treat
liver disease
parasitic infection
enzyme disease
What is genetic transfer
When viral replication is implicated and used for good
