Solutions - solubility

Question 1

Solution def.

Answer 1

Solute dissolved in a solvent at a molecular level

Question 2

Solvation def.

Answer 2

Process of binding solvent to solute

Question 3

Drug dissolution def.

Answer 3

spontaneous dissolving

Question 4

Factors affecting dissolution

Answer 4

Solute, solvent, pH, temp, co-solvents, additives

Question 5

Rate of solubility factors

Answer 5

Surface area, B/M point, functional groups, additives, pH, temp
Physical factors - crystallinity (amorphus faster rate), particle size, agitation
- affect rate not total solubility

Question 6

Saturated solution definition

Answer 6

Solutions which has the maximum amount of solute dissolvd in it

Question 7

Acidic/basic dissolution conditions

Answer 7

Acid insoluble in acid, base soluble in acid

Ionised form more soluble

Question 8

Methods to improve solubility

Answer 8

Co-solvency
Salt forms and changing pH
Hydrotropic salts 
Solubilisation - surfactant micelles
Complexation
Form amorphus crystal

Question 9

Salts to improve solubility

Answer 9

Dissociates more readily than non-salt form into conjugate base

Question 10

Co-solvency to improve solubility

Answer 10

Alters polarity of solvent meaning non-polar solutes will dissolve (like-like)

Question 11

Complexation to improve solubility

Answer 11

Cyclodextrins - Hydrophilic outside which can dissolve

API inside in hydrophobic sections

Question 12

Surfactants to improve solubility

Answer 12

hydrophilic tail, hydrophobic heads
Form micelles
Maximum additive conc = Max amount of drug in a micelle
NON-IONIC SURFACTANTS -