Suspension Part 1

Question 1

Contains undissolved or immiscible drug distributed (dispersed phase) throughout a vehicle (dispersing phase/
dispersion medium)

Answer 1

Dispersion system

Question 2

Preparations of Dispersion

Answer 2

Liquid or semi solid

Question 3

Types of dispersion system

Answer 3

Coarse dispersion
Fine dispersion
Colloidal dispersion

Question 4

Dispersed particles have a greater tendency to separate from the dispersion medium then settles at the bottom.

Answer 4

Coarse dispersion

Question 5

Particle size of Coarse dispersion

Answer 5

10-50 um

Question 6

Example of coarse dispersion

Answer 6

Suspensions and Emulsions

Question 7

Particle size of Fine Dispersion

Answer 7

0.5 to 10 um

Question 8

Particle size of Colloidal dispersion

Answer 8

1.0nm and 0.5 um

Question 9

A two-phase system containing insoluble or immiscible drug distributed throughout a vehicle.

Answer 9

Suspensions

Question 10

2 phases of suspension

Answer 10

Internal and external phase

Question 11

They are distributed evenly (usually the solid part); contains the active
ingredient

Answer 11

Internal phase aka suspensoid

Question 12

Usually the liquid part; the vehicle/ solvent

Answer 12

External phase aka suspending phase

Question 13

Characteristics of a suspension:

Answer 13

murky/cloudy, semi-transparent, usually thick/viscid like syrups but flowy in solutions

Question 14

Reasons for creating suspensions

Answer 14

1. Certain drugs are chemically unstable in solution but stable when suspended
2. Ideal dosage forms for patients who have difficulty of swallowing oral solid dosage forms
3. Can mask unpleasant taste of drugs because of the decreased contact of the drug that is unpalatable.
4. Some drugs are insoluble in all acceptable media
5. The liquid character ensures some uniformity of dosage
6. More stable than solutions

Question 15

Features Desired in a Pharmaceutical Suspension

Answer 15

1. Suspensoid should settle slowly
2. Suspensoid should be readily redispersed
3. The particle size of the suspensoid should remain fairly constant
4. The suspensoid should pour readily and evenly from its container
5. Should be acceptable to the patient

Question 16

Disadvantage of suspensoid settling down slowly

Answer 16

when it settles down, there will be an increase in the particle’s affinity forming now a hard mass. If this happens, the mass will not break up easily once the drug is shaken and if it will be broken it is in an irregular dose.

Question 17

settling of the suspended phase

Answer 17

Sedimentation Rate

Question 18

Stoke’s Equation

Answer 18

was derived for an ideal situation in which uniform, perfectly spherical particles in a very dilute suspension settles without producing turbulence, without colliding with other particles of the suspensoid, and without chemical or physical attraction or affinity for the dispersion medium.

Question 19

Factors Affecting Sedimentation Rate

Answer 19

1.Dispersion medium
2.Particle size of the suspensoid
3.Density of the suspensoid
4.Solid content

Question 20

The rate of sedimentation may be appreciably reduced by increasing the viscosity of the dispersion medium
(external phase).

Answer 20

Dispersion medium

Question 21

The velocity of fall of a suspended particle is greater for larger particles than it is for smaller particles (the smaller the particle size of the suspensiod, the easier the suspension will be poured)

Answer 21

Particle size of the suspensoid

Question 22

Particle size of the suspensoid

Answer 22

↑ particle size of a suspensoid:
↓ velocity of the suspended particle

Question 23

The density of the suspended particle should be greater than the density of the dispersion medium

Answer 23

Density of the suspensoid

Question 24

When density is decreased what happens to the suspensoid?

Answer 24

The suspensoid tends to float

Question 25

The viscosity characteristics of a suspension may be altered not only by the vehicle used, but also by the solids content.

Answer 25

Solid content

Question 26

Solid content

Answer 26

(↑solid content: ↑viscosity: ↓settlement of suspensoid)

Question 27

Physical Features of the Dispersed Phase of A suspension, In most good pharmaceutical suspensions

Answer 27

Diameter 1-50 um

Question 28

One of the most rapid, convenient and inexpensive methods of producing fine drug powders

Answer 28

Micropulverization
-10-50 um
-Used for oral and topical suspensions

Question 29

Produces the desired ultrafine or micronized particles by the shearing action of high velocity compressed airstreams on the particles in a confined space

Answer 29

Fluid energy grinding
-With size of 10um
-Used for parenteral & ophthalmic suspension

Question 30

A solution of a drug is sprayed and rapidly dried by a current of warm, dry air circulating in the cone.

Answer 30

Spray Drying
-Cone shaped