special dosage forms

Question 1

How are micelles formed?

Answer 1

surfactants

Question 2

sufactants

Answer 2

amphiphilic molecules described as having:

1) hydrophilic head
2) hydrophobic tail

Question 3

How do surfactants arrange in water?

Answer 3

to minimise contact between hydrophobic tail + solvent

Question 4

How are surfactants arranged in low concentrations?

Answer 4

align on surface of water

Question 5

How are surfactants arranged in high concentrations?

Answer 5

self-assemble to form micelles

Question 6

critical micellar concentration

Answer 6

concentration of surfactants above which micelles form

Question 7

What does osmotic pressure depend on?

Answer 7

concentration of solute in solution

Question 8

How can clinical micellar concentration be measured?

Answer 8

1) osmotic pressure
2) solubility of water insoluble molecules
3) light diffraction
4) surface tension
5) molar conductivity

Question 9

molar conductivity

Answer 9

conductivity of electrolyte solution divided by molar concentration of electrolyte

Question 10

What are phenolic compounds used for?

Answer 10

disinfection

Question 11

What happens when you add

surfactants to water below the CMC?

Answer 11

surfactants locate at liquid/air interface reducing surface tension of liquid

Question 12

What are liposomes formed from?

Answer 12

phospholipids

Question 13

How do liposomes assemble in water?

Answer 13

to form lipid bilayer

Question 14

Where do liposomes solubilise hydrophobic drugs?

Answer 14

bilayer

Question 15

Where do liposomes solubilise hydrophilic drugs?

Answer 15

water core

Question 16

What are liposomes used for?

Answer 16

1) protect drugs from degradation in vivo + prolong activity
2) reducing dose + side effect by drug targeting
3) favour absorption of drug through cellular membranes
4) oral/parental/transdermal/topical delivery of drugs

Question 17

What are the 4 types of liposomes?

Answer 17

1) conventional
2) stealth
3) targeted
4) cationic

Question 18

What are cyclodextrins used for?

Answer 18

1) increase aqueous solubility of drugs
2) increase chemical stability of drugs
3) enhance drug delivery to + through biological membranes
4) increase physical stability of drugs
5) convert liquid drugs to microcrystalline powders
6) prevent drug-drug/drug-excipient interactions
7) reduce local irritation after topical/oral administration