Solubility Flashcards Preview

Pharmaceutics > Solubility > Flashcards

Flashcards in Solubility Deck (16)
Loading flashcards...
1

Solution is..

a mixture of 2 or more components that form a single phase that is homogenous at the molecular level.

2

Solute is..

the component that is dissolved in the solvent in a solution

3

Solvent is..

the component that usually constitutes the bulk of the solution and determine its physical state.

4

Concentration is..

proportion of a solute in a solution

5

Solubility is..

the maximum solute concentration that can be achieved for a given solute in a solvent.

an attribute of the solute

6

Saturation point is where..

no more solute can dissolve.

7

Subsaturation is

where the solute concentration is below the saturation point / its solubility.

8

Dissolution does not mean

high solubility

9

Solubility depends on: (3)

temp
pressure
pH
another's

10

Like dissolves Like
2 examples:

matching characteristics

both polar / both non polar and the proportions of them

11

Explain the idea of polarity

highly electronegative bonded to a less electronegative

this can be predicted from structure

they allow dipole-dipole interactions, possibly hydrogen bonds and ion-dipole interactions

12

Gibbs free energy equation:

Delta G = Delta H - T delta S

DH = enthalpy change
DS = entropy change

13

Enthalpy of dissolution can be...

endothermic or exothermic

14

According to Gibbs free energy, what affects whether something dissolves:

If DG is - (exo)
solute can dissolve

if DG is + (endo)
solute cannot dissolve

15

Le Chatelier's Principle:

If a change in conditions is applied to a system in equilibrium. the equilibrium will shift to counteract the effect of the change.

this is why solubility changes.

16

The effect of pH on solubility:

acidic drug more soluble at higher pH

basic drug more soluble at low pH

ionised form more soluble than unionised drug