oral drug delivery

Question 1

what are the problems with oral delivery from pharmaceutics perspective?

Answer 1

its hard to get the drug to target

Question 2

how do drugs pass the intestinal mucosa?

Answer 2

create a steep concentration of the drug just outside the point of absorption.

Question 3

why do you need to be careful to control the release of the drug?

Answer 3

-Too fast – drug doesn’t reach epithelium
• Too slow – concentration gradient too shallow; drug does not
cross epithelium
Estimated ideal release time profile is 2-3 h.

Question 4

what is the role of mucus?

Answer 4

-protects epithelium against particulate damage and pathogenic attack;
-lubricates to allow passage of food through GI tract etc.;
hosts commensal bacteria;
-Selectively allows nutrients passage to the epithelium during digestion;
poses a barrier to the oral or nasal delivery of drugs.

Question 5

what does the absence of mucus lead to?

Answer 5

leads to colitis in the GI tract, dry eye syndrome in tear film;
modification of respiratory mucus in cystic fibrosis leads to inflammation and infection.

Question 6

what are mucins and what are the 2 different types?

Answer 6

-glycoprotein
2 types shorter which are anchered into cell membrane and other is secreted and is longer
they form mucus baarrier

Question 7

how do nanocarriers help circumvent the barrier and deliver drugs to the
systemic circulation?

Answer 7

• Improving drug solubility
• Improving drug permeability across the intestinal mucosa
• Targeted delivery?

Question 8

what are some problems with nanoscale forulations?

Answer 8

• Aggregation
• Complex, costly? delivery systems required
• Safety

Question 9

what do nanoparticles interact with when they enter the bloodstream?

Answer 9

blood opsonins

Question 10

what does Opsonin-mediated removal of nanoparticles depend on?

Answer 10

on np size, surface composition and

surface charge

Question 11

what determines whether substances are cleared renally or hepatically?

Answer 11

Glomerular filtration – molecules/particles below ~6-8 nm are efficiently
filtered by glomerulus, larger molecules/particles remain in the blood
• Mononuclear phagocytic system (MPS) – takes up larger particles – can retain
for months/years
• Surface coatings (e.g. PEG, dextrans) can help avoid opsonisation and MPS
uptake
• If too large for renal clearance and avoiding MPS, hepatic clearance will follow