Brainscape's Knowledge GenomeTM

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


See full index

Pharmaceutics > Nasal Route > Flashcards

Nasal Route Flashcards

1
Q

What do folds inside the nose do?

A

Increase SA = more area available for absorption

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

What are the therapeutic areas for nasal route?

A 
Nasal allergy
Nasal congestion
Nasal infection
Systemic therapy
Vaccine delivery
Access to CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Out of the therapeutic areas, which are local?

A

Nasal allergy
Nasal congestion
Nasal infection

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

What are advantages?

A 
Easy to administer 
Non-invasive, painless
Avoid 1st-pass
Low enzymatic activity
Direct route to brain
Potential to elicit rapid onset of action
Peptide delivery
Better systemic bioavailability than oral
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why does the nasal route avoid 1st-pass?

A

1 cell thick + good blood supply

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

What is the nasal cavity divided into?

A

2 halves by nasal septum

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

What is the nasal cavity covered in?

A

Mucus membrane containing goblet cells

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

Where does absorption occur in the nose?

A

Across turbinates + septum

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

How are lipophilic drugs transported?

A

Transcellularly by conc-dependent passive diffusion by receptor mediated + vesicular transport mechanisms

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

How are hydrophilic drugs transported?

A

Pass through epithelium via gaps between the cells (tight junctions)

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

What does it mean that hydrophilic drugs pass through tight junctions?

A

Limited to drug molecular size < 1000 Da

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

Describe nose brain pathway

A

Olfactory mucosa is in direct contact with the brain + cerebral spinal fluid

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

Why is the nose brain pathway important for drug transport?

A

Drug could potentially be absorbed across olfactory mucosa + enter CNS

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

What does the nose brain pathway offer?

A

Rapid, direct route for drug delivery to the brain, bypassing BBB

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

What is the nose brain pathway beneficial for?

A

Treatment of Parkinson’s disease, Alzheimer’s or pain

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

What is the function of the nose?

A

Passage for movement of air

Humidify + warm air

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

What happens to large particles trapped in nasal filter?

A

Undergo rapid clearance

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

What is important for local + systemic delivery?

A

Site of particle deposition + rate of clearance

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

Where are cilia found?

A

On surface of epithelial cells that transport mucus toward the nasopharynx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the function of mucociliary clearance?

A

To remove foreign substances from nasal cavity - this includes drugs

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

What is the normal mucociliary transit time?

A

12-15 mins

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

What does it mean that the normal mucociliary transit time is 12-15mins?

A

Drugs need to ideally be absorbed before this

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

What are the advantages of local delivery?

A

Deliver directly at site of action
Permit rapid relief at lower dose vs oral
Reduce systemic side effects

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

What are examples of nasal local delivery?

A

Nasal corticosteroids reduce nasal mucosa inflammation + sinuses without causing pituitary-adrenal suppression

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

When would systemic nasal delivery be used?

A

Emergency situation, where rapid onset of action required

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

What are examples of systemic nasal delivery?

A

Sumatriptan for migraine

Fentanyl for pain relief

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What can be delivered systemically?

A

Peptides

eg. desmopressin acetate = pituitary hormone for diabetes insipidus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the problem with peptide delivery?

A

Successful BUT low bioavailability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What factors affect systemic absorption?

A 
Solubility
Molecular size
Degree of ionisation 
Enzymatic activity
Mucosal contact time
Nasal epithelium permeability
30
Q

How is solubility a factor affecting systemic absorption?

A

Drugs must be in solution to be absorbed

Only 25-200 micro L can be administered intranasally

31
Q

Which drugs pose problems for systemic absorption?

A

Low aq solubility or drugs that require high doses

32
Q

How can solubility problems be overcome?

A

Formulating as suspension or powder in micro-size range
Different salt forms of ionisable drug
Use of excipients - eg. co-solvents
Modification of molecular form

33
Q

If formulating a drug as a suspension or powder in its micro-size, what is required?

A

Drug to be dissolved in nasal cavity before absorption

34
Q

How is molecular size a factor affecting systemic absorption?

A

Rate + extent of absorption decreases as molecular weight increases

35
Q

What size molecule has most efficient absorption?

A

< 1kDa

36
Q

Which particle size adheres to nasal mucosa the best?

A

10-50 microns

37
Q

Why do 10-50 microns sized particles adhere best to nasal mucosa?

A

Small particles pass to lungs

Larger impacted on anterior + run out of nose

38
Q

How is degree of ionisation a factor affecting systemic absorption?

A

Formulation pH has to be as close to nasal mucosa to minimise local irritation

39
Q

What is the pH of nasal mucosa surface?

A

7.4

40
Q

What is the pH of mucus?

A

5.5-6.5

41
Q

What pH is not tolerated?

A

3-10

42
Q

What can happen to local pH?

A

Can become alkaline in certain nasal conditions

eg. acute sinusitis + rhinitis

43
Q

Which drugs are better absorbed?

Degree of ionisation

A

Unionised with higher logP better absorbed than ionised form

44
Q

How is enzymatic activity a factor affecting systemic absorption?

A

Drugs may be metabolised in lumen or pass to epithelium

45
Q

Is the metabolic activity in nasal cavity still less than GI tract?

A

YES

46
Q

What enzymes are found in nasal cavity?

A

Broad range
Monooxygenase
Cytochrome P450s
Proteolytic enzymes

47
Q

How can enzymatic activity be overcome?

A

Enzyme inhibitors in formulation
Use of prodrugs
Encapsulate drug

48
Q

Why would use of prodrugs limit enzyme activity?

A

Reduce affinity of drug for enzyme

49
Q

Why would encapsulating drugs limit enzyme activity?

A

Limit enzyme access to drug

50
Q

How is mucosal contact time a factor affecting systemic absorption?

A

Increase residence time of drug in turbinates = increases drug absorption

51
Q

How can you increase residence time?

A

Mucoadhesive polymers

52
Q

What do mucoadhesive polymers do?

A

Prolong drug contact time with mucosa without being absorbed

53
Q

Does increasing contact time always increase absorption?

A

NO

eg. rate of diffusion decreases as viscosity increases

54
Q

Why do mucoadhesive polymers prolong contact time?

A

Increase viscosity = increase residence time

55
Q

What is viscosity limited to + why?

A

Limited to 500mPa.S

Otherwise too viscous

56
Q

How is nasal epithelium permeability a factor affecting systemic absorption?

A

Mucus layer = diffusion layer

57
Q

Which permeability is less affected?

A

Small, uncharged molecules compared to large, cationic or small hydrophobic molecules

58
Q

What can be added to increase permeability + what do they do?

A

Penetration enhancers

= alter epithelium structure temporarily

59
Q

What is in the nasal liquid formulation?

A 
API
Antimicrobial preservative 
Antioxidants
Solubilising agents/co-solvents
Salts to adjust pH
Humectants
Viscosity enhancers
Absorption enhancers
60
Q

Why are humectants in nasal liquid formulation?

A

To minimise irritation to the nose

61
Q

What are the different nasal devices?

A

Dropper/squeezer
Spray
Tube

62
Q

What pros of nasal dropper?

A

Cheap

Simple

63
Q

What are cons of nasal dropper?

A

Liquid can be delivered too quickly

Vol administered subject to patient technique

64
Q

Why is liquid being administered too quickly a con for dropper?

A

Can drip from nose to throat = cough

65
Q

When is dropper only suitable?

A

Drug with large therapeutic window

66
Q

Describe nasal spray

A

Solution or suspension formulated in metered dose pump or pre-filled syringe
Produce fine droplets

67
Q

What vol is delivered in nasal spray?

A

25-50 micro L

68
Q

What pros of nasal spray?

A

Exact dose delivered + spread across mucosa
Available as multi-dose or unit-dose
Easy + fast to administer

69
Q

What is the con of nasal spray?

A

Requires priming

70
Q

Describe nasal tube

A

For creams, gels + ointments for local effect

71
Q

What pros of nasal tube?

A

Easy to apply

Applied with finger or cotton bud

72
Q

What is the con of nasal tube?

A

Uncontrolled dose

Pharmaceutics (21 decks)

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