Suspension

Question 1

Suspensions have _____ dissolution/absorption than tablets

Answer 1

faster

Question 2

Suspensions have _______ dissolution/absorption than solutions

Answer 2

slower

Question 3

What are the three kinds of delivery routes in suspensions?

Answer 3

1. Oral
2. Externally applied
3. Parenteral

Question 4

What are the two classifications of suspensions?

Answer 4

1. Colloidal

2. Coarse

Question 5

What are the particle sizes in colloidal suspensions?

Answer 5

<1 micron

Question 6

Which classification of suspensions are always treated as suspensions?

Answer 6

Coarse

Question 7

Which classification of suspensions are treated as either suspensions or solution depending on the case?

Answer 7

Colloidal

Question 8

What are the particle sizes in coarse suspensions?

Answer 8

> 1 micron

Question 9

Which classification of suspensions settle under gravity?

Answer 9

Coarse

Question 10

Which classification of suspensions typically do not settle?

Answer 10

Colloidal

Question 11

A good pharmaceutical suspension has _____ sedimentation rate

Answer 11

slow

Question 12

Sedimentation rate is derived from ideal situations where particles are _____ and ____

Answer 12

uniform, spherical

Question 13

Sedimentation rate is derived from ideal situations where suspension is _______

Answer 13

dilute

Question 14

Sedimentation rate is derived from ideal situations where no _______ during particle settling

Answer 14

turbulence

Question 15

Sedimentation rate is derived from ideal situations where no particles ________ with each other

Answer 15

collide

Question 16

Sedimentation rate is derived from ideal situations where no _____ and _____ interactions between particles and medium

Answer 16

chemical, physical

Question 17

What is Stokes equation?

Answer 17

Rate of sedimentation =

d^2(particle density - medium density) * gravitation constant /(18 * viscosity of medium)

Question 18

Stokes equation does / does not apply directly to pharmaceutical preparations

Answer 18

does not

Question 19

T / F Suspensions will not always settle over time

Answer 19

False, eventually settle

Question 20

What happens if density of medium is greater than density of particles?

Answer 20

Particles float to surface

Question 21

Why is having particles floating to the surface a bad thing?

Answer 21

Although there is not settling, it makes dosing difficult

Question 22

What happens if density of particles is greater than density of medium?

Answer 22

Particles settle

Question 23

What happens if density of particles is MUCH greater than density of medium? What the problem with it?

Answer 23

Particles settle very fast

May be difficult to dose accurately

Question 24

Why is having particle sizes too small a problem?

Answer 24

Settles slowly, but forms hard cake

Question 25

Why is having particle sizes too large a problem?

Answer 25

Will settle fast, but will be easy to re-disperse

Question 26

Vehicle vs particle, which is easier to adjust?

Answer 26

Particles

Question 27

How easy is ti to re- distribute hard cakes?

Answer 27

It's not easy, it is to be avoided

Question 28

What is flocculation?

Answer 28

The process by which particles settle fast in a very loose/easy to redisperse mass

Question 29

What can you add to promote flocculation?

Answer 29

1. Clays in oral suspension 2. pH adjustment / electrolytes 3. Surfactants

Question 30

How does adding sufactants promote flocculation?

Answer 30

Wet particle surfaces + prevents them from sticking to each other

Question 31

How does adjusting pH and electrolytes promote flocculation?

Answer 31

Promotes ionic interaction to form a structure

Question 32

What kind of tension does surfactants bring to the lipophilic particle and the hydrophilic medium?

Answer 32

Interfacial tension

Question 33

How much wetting agent should you use when preparing suspensions? Why?

Answer 33

As little as possible Too much causes foaming, bad taste, dissolution of drug

Question 34

In general, drugs are ____ stable in liquid than solid form

Answer 34

less