Pharmaceutical Suspensions

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Questions and Answers

What is a suspension?

A liquid system comprising of a solid distributed throughout a liquid (correct)

A solid system comprising of a liquid distributed throughout a solid

A liquid system comprising of a gas distributed throughout a liquid

A gas system comprising of a solid distributed throughout a gas

What is the particle size range for colloidal suspension?

Up to 1 µm (correct)

Between 1 µm and 5 µm

Greater than 5 µm

Greater than 10 µm

Which of these is a reason for using suspensions?

Unpalatable active ingredients (correct)

Stable actives in solution

Soluble active ingredients

To ensure rapid release of the active ingredient

Which active ingredient is mentioned as being insoluble?

Ibuprofen Signup and view all the answers

What particle size range defines a coarse dispersion?

Greater than 1 µm Signup and view all the answers

What characteristic of a well-formulated suspension ensures it has a smooth texture?

Small particle size Signup and view all the answers

Which of the following is important for ensuring a well-formulated suspension can be administered successfully?

Homogeneous during administration Signup and view all the answers

To ensure a suspension is easily pourable, what property should its viscosity have?

Viscosity balanced between high enough to retard sedimentation and low enough to pour Signup and view all the answers

Which of these qualities is essential for a suspension to be re-dispersible?

Easily re-dispersible Signup and view all the answers

What is a key characteristic of well-formulated suspensions that helps retard sedimentation?

High viscosity Signup and view all the answers

Which agent is used to increase the viscosity in indiffusible solid suspensions?

Tragacanth Signup and view all the answers

What is the purpose of grinding particles in a mortar for indiffusible solid suspensions?

To control particle size Signup and view all the answers

Which of the following is a wetting agent used in indiffusible solid suspensions?

Glycerol Signup and view all the answers

What characterizes a deflocculated suspension compared to a flocculated one?

Pleasant appearance and difficult to re-disperse Signup and view all the answers

What is a characteristic of flocculated suspensions?

They form loose aggregates known as floccules Signup and view all the answers

Which agent is used to control the particle size in indiffusible solid suspensions?

Mortar Signup and view all the answers

Which of the following is a thickening agent used to increase viscosity in indiffusible solid suspensions?

Carboxymethylcellulose Signup and view all the answers

What characteristic describes deflocculated suspensions?

Forms a cake once settled Signup and view all the answers

Which of the following is a wetting agent?

Glycerol Signup and view all the answers

What happens to floccules in indiffusible solid suspensions?

They are loose aggregates Signup and view all the answers

What characteristic does a suspension of diffusible solids exhibit?

Easily dispersed in water and re-dispersed after settling Signup and view all the answers

Which type of suspension requires suspending agents?

Suspension of indiffusible solids Signup and view all the answers

Which equipment is used to work out lumps during the manufacture of diffusible solid suspensions?

Mortar and pestle Signup and view all the answers

At what stage are colourants, flavourants, and volatiles typically added in the manufacture of diffusible solid suspensions?

Towards the end Signup and view all the answers

What happens to insoluble solids during the preparation of diffusible solid suspensions?

They are dispersed in a small quantity of the liquid vehicle Signup and view all the answers

What is the first step in the manufacture of an indiffusible suspension?

Insoluble powders and dry suspending agents added to mortar Signup and view all the answers

Which step involves dissolving soluble solids in the vehicle?

Step 4 Signup and view all the answers

What is characterized as forming pure clumps and not readily dispersing in water?

Indiffusible powders Signup and view all the answers

Which property is NOT associated with diffusible powders?

Form pure clumps Signup and view all the answers

When are colorants, flavourants, and volatiles added in the manufacture process?

Just prior to making to volume Signup and view all the answers

Which of the following is a natural polysaccharide?

Tragacanth Signup and view all the answers

Which category does Bentonite belong to?

Clays Signup and view all the answers

Which option is a semi-synthetic polysaccharide?

Methylcellulose Signup and view all the answers

Which of these is a synthetic thickener?

Carbomer Signup and view all the answers

What type of suspending agent is Acacia?

Natural polysaccharide Signup and view all the answers

Study Notes

Suspension Defined

A suspension is a liquid system comprising of a solid (disperse phase) distributed throughout a liquid (continuous phase)
There are two types of suspensions: colloidal suspension (particle size up to 1 µm) and coarse dispersion (particle size > 1 µm)

Importance of Suspensions

Insoluble active ingredients (e.g. Ibuprofen) require suspension formulation
Unstable actives in solution (e.g. Amoxycillin) can be stabilized through suspension
Unpalatable active ingredients can be masked through suspension
Suspensions allow control over the rate of release

Characteristics of Well-Formulated Suspensions

Homogeneous during administration
Easily re-dispersible
Optimal viscosity to retard sedimentation and facilitate pouring
Small particle size for a smooth texture

Types of Suspensions

Suspension of diffusible solids: easily wetted by water, mixes readily, and stays dispersed long enough to administer a dose
Suspension of indiffusible solids: does not disperse readily in water, forms porous clumps, and requires suspending agents

Method of Manufacture (Diffusible)

Disperse solids in a small quantity of liquid vehicle
Work out lumps using a mortar and pestle
Dissolve soluble solids in the vehicle and add
Add colourants, flavourants, and volatiles towards the end

Formulation of Indiffusible Solid Suspensions

Control particle size by grinding in a mortar
Use thickening agents to increase viscosity (e.g. Tragacanth, Carboxymethylcellulose)
Use wetting agents (e.g. Glycerol, Propylene glycol)

Flocculation

Floccules are loose aggregates with a high settling rate, but are easily re-dispersed
Deflocculated suspensions have a pleasant appearance but form a cake that is difficult to re-disperse
Many suspending agents flocculate to an extent

Suspending Agents

Natural polysaccharides (e.g. Tragacanth, Acacia)
Semi-synthetic polysaccharides (e.g. Methylcellulose)
Clays (e.g. Bentonite, Magnesium aluminum silicate)
Synthetic thickeners (e.g. Carbomer, Colloidal silicon dioxide)

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Description

Learn about suspensions, a type of liquid system used in pharmaceuticals, including types of suspensions and their importance in drug development.