Suspensions as doasge forms

Question 1

Susension adv & disadv

Answer 1

Advantages Disadvantages
Low solubility drugs unstable
mask taste uneven settling
Swallowing problems Bulky & inconvenient
can control drug delivery Unaesthetic
rate

Question 2

Desired features

Answer 2

Settle slowly
Particle size remain constant
Pour readily and easily

Question 3

Suspension parameters

Answer 3

Dispersed phase - Particle size, surface properties

Vehicle - viscosity, electrlytes, surfactants

Question 4

Repulsive forces

Answer 4

DVLO electric double layer

Steric hindrance - hydrated surfaces repulsion

Question 5

DVLO theory

Answer 5

Vt = Va + Vr
- +
Ideal = repulsive slightly higher than attractive
Deliberate flocculation,

Question 6

Repulsion between hydrated surfaces

Answer 6

+ve enthalpy, -ve entropy

Question 7

Suspension excipients

Answer 7

Vehicle
Electrolytes
Surfactants
hydrophilic polymers
Preservatives, sweeteners
antioxidants
Wetting agents - reduce tension between particle and dispersed medium. prevent trapped air

Question 8

Flocculating agents

Answer 8

Electrolytes - reduce double layer thickness
Surfactants
Hydrophilic polymers

Question 9

Suspension stablity test

Answer 9

sedimentations layer:total volume