L13 - Suspensions - Introduction

Question 1

what im a solution in pharmacy terms

Answer 1

• solution is a liquid system
• formed from various combination of phases
• at the end the solution is a one-phase system where at equilibrium all the ingredients are disperased eenly at the molecular level

Question 2

in a solution: what are the other components added to make up a formulation

3 examples

Answer 2

• preservatves
• buffers
• flavours

Question 3

What is a characteristic of the appearance of a solution

Answer 3

• opticaly clear

Question 4

what is a suspension

Answer 4

• a dispersion of solid materials, generally the drug, in a liquid phase

Question 5

what are the differences in pharmacy between a solution and a suspension

Answer 5

• solid material (usually the drug) does not dissolve in the liquid phase in a suspension#
  
  • drug remains as solid particles
  • these particles are distributed throughout the liqud phase

Question 6

what is the dispersed phased and the liquid phase

Answer 6

• a suspension describes a dispersion of solid materials (the dispersed phase) in liquid (the continuous phase)

Question 7

in general term, in a suspension, what influences the physical and chemical behaviour

Answer 7

particle size

Question 8

what are the typical size of particles in a pharmaceutical suspension?

what are the different types of suspension

Answer 8

• particle size in typical pharmaceutical suspension are between 0.1µm and 10µm
• colloidal suspension
  
  • upto 1µm
• coarse suspension
  
  • >1µm

Question 9

what is the appearance of suspension

how does it change

Answer 9

• suspension are not opotically clear and appear cloudy unless the size of the particles is within the colloidal range

Question 10

what is the rational of pharmaceutical suspension

Answer 10

• durgs with low solubility in the contineous phase
• patient acceptability
  
  • a liquid form, rather than a solid dosage form
• drugs that have an unpleasant taste in soluble form can be made into insoluble form
  
  • more palatable
  • e.g. chloramphenicol (soluble) → chloramphenicol palmitate (insolbule)
• oral suspension
  
  • drug already finely divided form → optimal dissolution in GI tract → increased absorbtiion
• stability
  
  • freshly prepared just before use
• modify drug release