Diffusion and Dissolution

Question 1

What are the 3 types of diffusion?

Answer 1

Porous membrane
Fiborous
Semi-Permeable

Question 2

What is flux?

Answer 2

Amount of material flowing through a cross-section of a barrier in a specific amount of time

Question 3

Is flux only positive, only negative, or can it be both?

Answer 3

Flux is always positive

Question 4

What defines Steady State conditions?

Answer 4

Sink conditions (when concentration in receptor compartment is always 0)

Question 5

What are Non-Steady State Conditions?

Answer 5

Lag time for compound to establish a uniform concentration gradient within the membrane that separates the donor and receiver compartments.

Question 6

What does dissolution testing help determine?

Answer 6

Stability

Shelf-life

Question 7

Diffusion coefficient

Answer 7

D

cm2/sec

Question 8

Permeability

Answer 8

P

cm/sec

Question 9

Partition Coefficient

Answer 9

K

Constant

Question 10

Concentration

Answer 10

C

mg/cm3

Question 11

Time

Answer 11

t

sec

Question 12

Volume (mL)

Answer 12

V

cm3

Question 13

Dissolution Rate Constant

Answer 13

k

cm/sec

Question 14

What are the 7 factors affecting dissolution rate?

Answer 14

Solubility
Wetting
Particle size
Crystalline state
Hydration
Complexation
Additives