Brainscape's Knowledge GenomeTM

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


See full index

The Medicine (Y2) > Extraction and sample preparation > Flashcards

Extraction and sample preparation Flashcards

1
Q

Define menstruum

A

Solvent(s) used in the extraction process

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

Define marc

A

Insolube materials (waste) left after extraction

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

What is a galencial?

A

A medicinal extract or tincture derived mainly from natural sources

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

What are the four types of extracts?

A

Tinctures
Liquid extracts
Soft extracts
Dry extracts

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

Soft extracts are semi-solid preparations obtained by evaporation or partial evaporation of the solvent used for extraction. True or false?

A

True

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

What are the 3 main steps in the extraction process?

A

Comminution - physically reducing plant material to particular size
Incubation with menstruum
Separating off marc

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

What are the rate limiting factors of the extraction process?

A

Wetting of the surface of particles
Permeability of cell walls
Rate of dissolution of cell contents
Outward diffusion of the solution

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

What are the methods of galencial preparations?

A 
Infusion
Decoction
Maceration
Percolation
Continuous hot extraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is meant by infusion?

A

Drug stood in hot/cold water for a short time

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

What is meant by decoction?

A

Extraction of soluble material by boiling plant in water for specified time

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

What is maceration?

A

Pronlonged infusion (days) in aq alcohol and a closed container

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

What is percolation?

A

Maceration and then flow of fresh solvent passing over ground material at a specified rate

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

What is continuous hot extraction?

A

Repeated infusion with hot solvent

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

What determines the method of extraction that is used?

A 
Pharmacognosy 
Hard
Soft
Unstable to heat
Cost
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why is sample preparation needed?

A

Isolate drugs of interest from complex matrices
Concentrate the analyte
Derivatise the analyte
Stabilise the analyte from undue degradation

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

Most organic solvent are lighter than water so float on top, what is the exception?

A

Chlorinated solvents

17
Q

The aim of acid-base extractions is to get drug into aqueous layer. True or false?

A

False - organic layer

18
Q

Phenobarbital is a basic drug. True or false?

A

False - acidic drug

19
Q

Lowering the pH of environment of phenobarbital will make it more soluble in organic solvents. True or false?

A

True

20
Q

Procaine is a basic drug. True or false?

A

True

21
Q

Increasing pH in which procaine is in will lead to it being more soluble in organic solvents. True or false?

A

True

22
Q

Aspirin is a weakly acidic drug. What is the best way to get it into organic phase?

A

React it with a weak acid (rather than base) so it remains unionised and gets into the organic phase

23
Q

What is the best way to extract alkaloids?

A

They are nitrogen containing bases so treat with a base to deprotonate and extract

24
Q

What is rotary evaporation?

A

Vacuum and heat - solute gets separated

25
Q

If a sample has a high boiling point, rotary evaporation is not a good method of extraction. Why?

A

Because heat will degrade the drug

26
Q

When is distillation used to separate miscible phases?

A

If the two components in the extract have different boiling points

27
Q

When is crystallisation used to separate miscible phases?

A

Components of the extract have different solubilities

28
Q

What is sublimation?

A

Freeze-drying

29
Q

Which extraction process involves the use of a lyophiliser and how is it used?

A

Sublimation -
Freeze sample so mixture becomes solid
Apply vacuum to sublimate ice directly into water vapour
Keep drawing off water vapour - usually waste
Solid product recovered in flask

30
Q

What is the key advantage of sublimation?

A

Can be used for heat-labile compounds e.g. biologicals, vaccines etc.

31
Q

What are the advantages of solid-phase extraction over liquid-liquid extraction?

A

Less labour
Less solvent used
Quick
Easier to automate

32
Q

How does solid phase extraction work?

A

The sample is filtered through sorbent particles
Analytes are captured from liquid matrix
Concentrated analytes are eluted with the solvent
Eluted sample is collected

The Medicine (Y2) (34 decks)

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