Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

The Medicine 2 - Sem 2 > Mixing > Flashcards

Mixing Flashcards

1
Q

What is a homogeneous system?

A

a particle system where the concentration of all elements is uniform

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which parameters should be tested during the mixing process?

A

the degree of mixing, efficiency of mixer and time necessary to achieve required degree of mixing & the components and their properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is meant by a positive mixture?

A

Components mix spontaneously and irreversibly by diffusion (almost perfect mix is achieved) e.g. miscible liquids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens in a negative mixture?

A

Components tend to separate, and they need a constant input energy to maintain the desired dispersion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Positive mixtures require a high degree of mixing efficiency. True or false?

A

false, negative mixtures do

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens in a neutral mixture?

A

The components have no tendency to either mix or to separate spontaneously.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

It is possible to separate a neutral mixture, but energy is required to do this. True or false?

A

false, no energy is required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is meant by a random mixture?

A

The components are perfectly mixed, hence the probability of selecting x type of particle is the same in all positions in the mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

During the manufacturing process, mixtures can change due to physical modification. True or false?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

If you decrease the solvent viscosity, a negative suspension will shift to a neutral mixture. True or false?

A

False, if you increase viscosity this will happen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens in ordered mixing?

A

The components are not independent of each other, resulting in a “spontaneous” degree of order in the mix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which type of mixture is driven by adhesive and cohesive forces

A

ordered mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the scale of scrutiny?

A

The amount of material (in weight or volume) used to test the quality of a mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the most appropriate scale of scrutiny to guarantee the strength of a 200mg tablet?

A

200mg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The higher the concentration of active drug in the mixture, the harder it is to test to quality of the mixing process. True or false?

A

false, the lower the conc the harder it is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

An already formed random mix is capable of changing to a non-random mix. True or false?

A

True

17
Q

What are the 3 types of mixers?

A

Batch, Semi-batch & continuous

18
Q

What factors cause segregation to occur?

A

particles differing in size, shape, density

19
Q

What are the 3 types of mixing for solids?

A
  1. convective: involves bulk movement or gross displacement of particles within mixture
  2. shear: happens when particles have different velocities
  3. Diffusion: caused by random motion of particles
20
Q

Which type of mixing is preferred with potent/active drugs?

A

diffusive mixing

21
Q

Which type of mixing is preferred with particles with a tendency to aggregate?

A

High shear mixing

22
Q

Which mechanism of mixing is macroscopic and relatively quick, involving the transfer of a large group of powder through the powder bed?

A

Convection

23
Q

Which mechanism of mixing is known as interface mixing and involved the flow of one layer of material over another layer, resulting in moving layers at different speeds?

A

Shear

24
Q

Which mechanism of mixing allows a true movement of individual particles to achieve a true random mix, where the powder bed is forced to move and the movement generates space between particles?

A

Diffusion

25
Q

In a mixing process, more than one mechanism is likely to occur. True or false?

A

True

26
Q

What are the 3 mechanisms of mixing liquids?

A

bulk transport, turbulent mixing & diffusion

27
Q

Which components are used to mix liquids?

A

to achieve an acceptable degree of mixing (i.e. random mix) all these three mechanism are required

28
Q

What is the typical powder weight that is used in a tumbling mixer?

A

50g to 100kg

29
Q

A tumbling mixer is generally used in the blending of excipients prior to tabletting. True or false?

A

True

30
Q

There is high risk of “deep spot” with non-mixed materials in propeller mixers. True or false?

A

false, in planetary mixers

31
Q

What is the importance of mixing?

A

– to ensure the quality of pharmaceutical products, provide an even distribution of active components and other ingredients, guarantee drug release with the desired rate, give an even appearance to dosage forms

32
Q

Turbine mixers are suitable for viscous fluids.

A

True

33
Q

Segregation can be minimised by using a similar size of drug and excipient. True or false?

A

True

The Medicine 2 - Sem 2 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions