Colloids: Formulating suspensions

What is a suspension?

mixture of water and non dissolved materials

Why is a suspension used?

- The drug is. not sufficiently water soluble for the required dose.

- Stability of the drug is poor.

What needs to be controlled in order to make a suspension?

- Solubility of drug, may require suppressing of drug solubility to ensure consistent doses.

- Maintenance of pH.

- Adding of anti-solvent.

What excipients can be added to suspensions?

- Flavourings and colours.

- Buffers and stabilisers.

- Viscosity modifiers.

- Wetting agents

- Flocculation modifiers.

How can patient adherence be increased?

Addition of flavourings and colours which increase palatability

What are antimicrobial preservatives?

Prevent microbial growth in suspensions.

How is viscosity controlled in suspensions?

- Using excipients such as Acacia and Silicates.

- Can also use alginates and celluloses.

What is the humectant effect?

Increasing viscosity also reduces evaporation of water (continuous phase).