intro to dissolution and solubility

Question 1

what drugs can be absorbed

Answer 1

generally only drugs in solution

Question 2

what is a solution

Answer 2

a mix of two or more components that form a single, molecularly homogenous phase

Question 3

what is dissolution

Answer 3

the process by which a solid dissolves in a solvent to produce a solution

Question 4

what drugs can cross the intestinal wall and be absorbed into the systemic circulation

Answer 4

generally only drugs in solution

Question 5

definition of a solubility

Answer 5

the amount that goes into a solution when equilibrium is established between the solute in solution and the excess substance

Question 6

diffusion process

Answer 6

1. molecules leaves the solid
2. molecule diffuses across h - rate determining
3. molecule leaves the diffuse layer for the well stirred bulk

Question 7

what affects surface area in Noye-Whitney equation

Answer 7

size of solid particles -
area increases as particle size reduces.
more porous particles have bigger surface area

Question 8

what affects Cs in Noye-Whitney equation

Answer 8

solubility in dissolution medium
temperature

Question 9

what affects C in Noye-Whitney equation

Answer 9

volume of dissolution medium

Question 10

what affects D in Noye-Whitney equation

Answer 10

dissolution medium viscosity

Question 11

what affects h in Noye-Whitney equation

Answer 11

degree of agitation (eg mixing)

Question 12

how does stomach contents affect drug dissolution

Answer 12

• food components
• pH
• buffer capacity

Question 13

how does GI motility affect drug dissolution

Answer 13

• transit/emptying of stomach
• GI secretions
• co-administered fluids