Brainscape's Knowledge GenomeTM

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


See full index

PHA223 > Lipid emulsions/parenteral nutrition (Cheng) > Flashcards

Lipid emulsions/parenteral nutrition (Cheng) Flashcards

1
Q

What is a parenteral lipid emulsion made from?

A

oil in water system

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

size of droplets in aliquid emulsion

A

90% < 1 micro m

typically 0.2 - 0.6 micro m

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

Are liquid emulsions stable?

A

no

thermodynamically unstable

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

shelf life of lipid emulsions

A

18-24 months at room temperature

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

2 phases in a parenteral lipid emulsion

A
  1. aqueous phase - WFI (water for injection)

2. triglycerides (oily phase)

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

triglyceride component of a lipid emulsion

A 
oil core
source of FAs
long chain TGs, medium chain TGs
mixture of LCTG and MCTG
structured lipids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How are structured lipids made?

A

esterification os MCFA (medium chain) and LCFA to form mixed TGs by heat

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

examples of emilsifiers for lipid emulsions

A

phospholipid from egg or soya lecithin

  • lipoid E100
  • Ovothin 200
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

structure of emulsifiers

A
  • acyl chains typically C16-C18
  • phospholipid head group
  • charged stabilisation
  • ionisation behaviour
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What type of molecules ar phospholipids?

A

amphiphilic

- can interact with lipid and aqueous surroundings

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

When does phase transitional temperature increase?

A

with increasing FA chain length

  • > van der Waals stronger
  • > need more energy to disrupt the packing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does putting a double bond in the chain affect the phase transitional temperature?

A

requires a much lower temperature to induce order packing rearrangement
-> lowers transitional temperature

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

What does the transitional temp affect?

A
  • product stability
  • how lipid emulsions can be produced

-> high transitional temp - hard to filter and high melting temperature

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

How parenteral lipid emulsions are manufactured?

A
  • oil phase mixed with high shear mixer in aqueous phase
  • creates a coarse emulsion
  • microfluidisation using high P pump
  • cooled in ice bath
  • fine emulsion created
  • coarse filtration (5 micro m)
  • heat sterilisaion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What variables affect properties of lipid emulsion?

A
  1. process parameters
    - temeraute
    - pressure
    - homogeniser passes
  2. formulation considerations
    - oil conc
    - emulsifier conc
    - salt/electrolyte conc
    - pH
    - drug conc/properties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does temperature affect droplet size?

A

inc temp - reduces viscosity

-> smaller droplet size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does oil conc affect properties of lipid emulsion?

A

increased oil concentration gives larger droplet sizes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does emulsifier concentration affect lipid emulsions?

A

more emulsifier gives narrow size distribution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How can salt conc affact lipid emulsions?

A

affects size distribution

  • affects electrostatic repulsive effects of phospholipids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does pH affact lipid emulsion?

A

increased pH gives better physical stability to the emulsion

-> because phospholipids can be hydrolysed at lower pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is parenteral nutrition?

A

supply of nutrients bypassing the digestive tract
- non-functioning GIT

(can’t take food orally)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is enteral nutrition?

A

nutrition given by oesophagus

```
functioning GIT
sip/tube feeding
~~~

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

PPN

A

partial parenteral nutrition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is PPN (partial/peripheral parenteral nutrition)?

A

supplement diet for patients who take food orally

can’t digest normal food properly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How is PPN given?

A

peripheral intravenous catheter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

2 types of PPN

A

lipid emulsion

amino acid-dextrose solution

27
Q

osmolarity and pH of PPN

A

< 900 mocmo/L

pH 7.2

28
Q

problems with PPN and how to reduce this

A

phlebitis

  • keep osmolarity < 900 mosmo/L
  • keep pH around 7.2
29
Q

brand od PPN

A

Nutriflex Peri

30
Q

TPN

A

total peranteral nutrition

complete parenteral nutrition

31
Q

What do TPN contain?

A 
proteins
dextrose
electrolytes
minerals
trace elements
insulin (based on patient's need)
32
Q

How is TPN given?

A

central venous catheter with infusion pump

  • subclavian or jugular
33
Q

steps for compounding/dispensing parenteral nutrition

A
  • review PN Rx
  • risk assessment
  • mixing
  • base solutions
  • add electrolytes/additives
  • label and check final product
34
Q

What components have high omolarity in the solutions?

A

amino acis

dextrose

35
Q

amino acid component of the base solution

A
  • self buffered
  • standard
    or
  • special formulations (renal/hepatic impairment/hypermetabolic conditions and children)
36
Q

What does the glucose part of the base solution contribute to?

A

osmolarity of the PN solution

eg. dextrose - acidic

37
Q

examples of the composition of lipid supplement in the base solution

A

soya bean oil

medium chain TGs

38
Q

mixing sequence for PN

A
  1. mix glucose with AA
  2. add electrolytes
  3. mix lipids
  4. add vitamins last
39
Q

Why can precipitation occur during mixing?

A

due to the order of adding ingredients or because of storage (slow crystallisation)

40
Q

What usually precipitates in PN solution?

A

calcium phosphate salts

  • can cause death if delivered
41
Q

How to stop precipitation in PN solutions?

A

adjust pH to favour formation of monoobasic phosphate salt

42
Q

What does the conc of free ca ions depend on?

A

Ca and AA sources

temperature

43
Q

What form of Ca phosphate salts precipitates?

A

dibasic phosphate salt

44
Q

How to reduce likelihood of precipitation?

A
  • adjust the mixing sequence: add phosphate first, thoroughly mix then add Ca
  • mix the 2 salts separately (P with AA and Ca with glucose), then combine these slowly
45
Q

Will precipitated crystals redissolve?

A

no

46
Q

What is the least stable ingredient of PN mixtures?

A

vitamins

47
Q

When should vitamins be added to PN mixtures?

A

immediately before infusion

48
Q

How are vitamins broken down?

A

by light and dissolved oxygen

49
Q

What do vitamins interact with in PN?

A

packaging materials of the infusion equipment

50
Q

What vitamin are most sensitive to UV light?

A

retinol (vit A source)

51
Q

How to avoid breakdown of retinol in PN mixtures

A
  • use overwrap
  • administer at night or away from daylight
  • use palmitate rather than acetate forms to avoid sorption loss through infucion equipment
52
Q

What vitamin is the most unstable?

A

vitamin C

  • > readily reacts with O molecules
  • > converted to DHA via oxidation
  • > can convert to oxalic acid (toxic)
53
Q

What are sources of oxygen that can cause oxidation of Vit C?

A
  • dissolved air in infusion bag
  • aeration of infusion during material transfers
  • residual air in compounded bag after sealing
  • air transmission through bag wall (storage)
54
Q

What accelerates/reduced oxidation?

A

accelerated by trace elements (esp copper)

reduced by cysteine

55
Q

What should the AA conc of PN be?

A

> 2.5%

56
Q

What should the pH of PN be?

A

pH > 5

57
Q

What should the dextrose conc of PN be?

A

> 3.3%

58
Q

What shouldn’t be mixed directly with lipid?

A

dextrose

59
Q

When should lipid be added?

A

last when all components are mixed

60
Q

What filters should be used for in line filtration of 2-in-1 and 3-in-1 formulations?

A
  1. 2 mcm for 2-in-1

1. 2 mcm for 3-in-1

61
Q

How often should filters be changed?

A

every 24hrs

62
Q

What does high concs of Ca and phosphorus form?

A

calcium phosphate - insoluble precipitate

63
Q

How to prevent precipitation?

A
  • AA conc > 2.5% + cycteine
  • pH 5 - 6
  • infuse solution within 24hrs of preparation
  • use calcium gluconate instead of calcium chloride
  • avoid mixing Ca and P close together during prep
  • total Ca+P amt < 45 mEq/L
    • > Ca:P 1:2

PHA223 (43 decks)

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