PHRD5925 Pharmaceutics Lecture 11 - Drug Absorption (Part 1)

5 physiological factors affecting oral drug absorption

what part of the GI has the highest surface area?

rank GI surface area

drug form that is more lipid soluble & better (passively) transported

3 parameters involved in the pH-partition theory

pH in relation to drug absorption from stomach

pH in relation to drug absorption from the intestine

Henderson-Hasselbalch equation

for a given pKa, _____ (increasing/decreasing) pH increases absorption of a weak acid

for a given pKa, _____ (increasing/decreasing) pH increases absorption of a weak base

normal low bulk or liquid intake takes ____ min to empty from the stomach

effect of delayed stomach emptying on the rate of drug absorption

effect of hot contents on gastric emptying rate

effect of aggression on gastric emptying rate

effect of lying on left hand side on gastric emptying rate

when increased rate of gastric emptying has a favorable effect (2)

when decreased gastric emptying rate has a favorable effect (2)

the quicker the stomach emptying, the ____ the plasma concentration

3 ways food effects drug absorption

- absorption occurs by passing through the intestinal cells
- most significant route of drug transport

- absorption occurs by transport  between intestinal cells (aqueous tight junctions)
- small hydrophilic cations are best candidates

what happens to tight junctions from the SI to colon?

best candidates for transcellular transport

major example of an efflux transporter