E6 The chemical basis of drug action

Question 1

What are the two main ingredients of raft forming agents?

Answer 1

an alginate

a gas forming agent

Question 2

Are most alginic acid and metal alginates insoluble in water?

Answer 2

yes

Question 3

Are most metal salts of alginates soluble in water?

Answer 3

yes

Question 4

How do alginic acids work as raft forming agents?

Answer 4

if pH drops below 3.5 alginic acid precipitates as a gel
precipitate/gel absorbs water
raft formed

Question 5

Many alginate based medicines also contain bicarbonate or carbonate, how do these work in acid?

Answer 5

the bicarb/carb produces CO2
soluble alginate reacts to form insoluble alginic acid precipitate/gel
the precip/gel traps CO2, produces low density raft (viscous foam) which floats on top of stomach contents

Question 6

What are the effects of calcium ions with alginate/alginic acid?

Answer 6

calcium cations interact with alginates/alginic acid and aid cross linking in the polymer, this increases the viscosity of the gel/raft

Question 7

What makes simeticone?

Answer 7

dimeticone & silica

Question 8

How does simeticone work?

Answer 8

alters the surface tension of small gas bubbles so they can co join to form larger bubbles, allows base in stomach to be more easy lost

Question 9

What are heterocycles?

Answer 9

rings that contain atoms and other non carbon atoms