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PY352 > Intranasal Drug Delivery > Flashcards

Intranasal Drug Delivery Flashcards

1
Q

What are some reasons for nasal drug delivery?

A
  • Local effects
  • Vaccines
  • Delivery to brain
  • Systemic effects
    (where oral route is not available because drug gets destroyed in GI fluids/ metabolised in gut wall or under goes liver first pass metabolism)
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2
Q

What are the main nasal passages?

A

Turbinates and meatuses

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3
Q

What are the cell types in nasal respiratory epithelium?

A
  • ciliated columnar cell
  • basal cell
  • goblet cell
  • non ciliated columnar cell covered with microvilli
  • tight junctions
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4
Q

Microvilli increase

A

surface area

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5
Q

What type of cell are turbinates and meatuses?

A

ciliated columnar cells

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6
Q

what do the turbinates and meatuses have to increase surface area?

A

convolutions

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7
Q

Example of a non ciliated type cell?

A

Olfactory region

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8
Q

What are the main functions of the nose?

A

Air conditioning and Filtration

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9
Q

How does the structure of the nose allow air conditioning to occur?

A

The structure of the nose allows for intimate contact between inspired air and mucosal surfaces

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10
Q

What does air conditioning do?

A

Increases temperature from 23 to 32

Increases humidity from 40% to 98%

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11
Q

Filtration allows removal of both

A

small and large particles

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12
Q

Large particles > ___micron are filtered by ________
Small particles ( __ to __ microns) are filtered by _______________.
Particles

A 
10
vibrissae
5 to 10
mucociliary clearance
2
not filtered out and may enter lungs
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13
Q

Mucociliary clearance is the _______ mechanism of the body

A

defence

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14
Q

Dust and microorganisms are deposited on ______ which is moved by tips of ____ to the ___________ where mucus and particles are ________ or expectorated.

A

mucus
cilia
nasopharynx
swallowed

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15
Q

Which two structures help with humidification?

A

Periciliary fluid

Mucus

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16
Q

What does mucus comprise of?

A 
Water (90-95%)
Mucin (0.5-5%)
Salts (1-2%)
Lipids (upto 30% of non aqueous solution)
IgA
Lysozyme
Lactoferrin
17
Q

Mucin is anionic/ cationic as it is ______ charged

A

anionic

negatively

18
Q

Main functions of nose is ___ ______ and ______ but the lesser function is _______. Approximately ____% of airflow is directed up to this portion of nasal cavity

A

air conditioning
olfacation
20

19
Q

What are the benefits of local + topical delivery?

A
  • rapid symptomatic relief because drug applied to site of action
  • decreased systemic side effects because much lower dose is used than when delivered systemically. Also no sedation with antihistamines in contrast to when given orally.
20
Q

What are some examples of local + topic drugs?

A

Decongestant e.g ipratropium Br
Anti-histamine e.g azelastine HCl
Corticosteroid e.g. budesonide

21
Q

What are some formulation factors to consider for nasal drug delivery?

A
  • pH (ionisation - drug pH should not irritate physiological pH of nose which is 5.5-6.5) CAN use 4.5 using HCl
  • Concentration (32 ug per spray micronised in suspension)
  • Volume (100-150ul can be inserted per nostril)
  • Viscosity (retention time) - use microcrystalline cellulose.
  • Solubility (20ug/ml)
  • Osmolarity (tolerability) - around 5% w/v dextrose
  • Preservatives (potassium sorbate)
  • Delivery device (metered dose/manual pump spray)
  • Penetration enhancers
22
Q

Vaccines target __ __ __ __.
There is no requirement for ______ and no ______ are involved (compared to other vaccines). An example of a nasal vaccine is _____

A

NALT - nasal associated lymphoid tissue.
sterility
needles
Flumist

23
Q

What are factors that affect nasal absorption? Give an example of each

A

Patient factors
Drug factors - charge, MW, lipohilicity
Formulation factors - pH, solubility
Physiological/anatomical factors - mucociliary clearance

24
Q

What are the anatomical advantages of nose?

A
  • highly vascular
  • large surface area
  • avoids first pass hepatic metabolism
25
Q

What are the anatomical disadvantages of nose?

A
  • contact time; mucocilliary clearance
  • immunological clearance
  • epithelial barrier
  • mucosal barrier
  • metabolic activity
26
Q

When spray is pressed, drug enters __________ then ______ and then finally _________ where it is swallowed

A

deposition site
turbinates
nasopharynx

27
Q

What are the drug factors that affect nasal absorption?

A
  • Lipophilicity (absorption increases with increased lipophilicty)
  • Charge (absorption best if molecule is uncharged)
    MW (absroption decreases when MW >1000Da.
28
Q

Hydrophillic drugs are transported by _________ route

A

paracellular

29
Q

If a drug is polar or water soluble and requires something to enhance the absorption, what can you give? Give an example also

A

Penetration enhancer

Chitosan

30
Q

How does Chitosan (penetration enhancer) work?

A
  • Acts as a bioadhesive
  • Transiently opens tight junction and therefore allows paracellular transportation of polar molecules, hence increased absorption
31
Q

What is the ideal treatment of short-duration breakthrough pain?

A

Rapid acting opioid of relatively short duration and no accumulation of opioid (to avoid opioid toxicity)

32
Q

Other than Chitosan, what other penetration enhancers are there?

A 
Bile salt
Chelators
Polymers
Tight junction-modulating peptides
Lipids and surfactants
33
Q

What are some therapeutic areas suitable for IN administration?

A
  • Emergency situation e.g. glucagon for insulin induced hypoglycaemia
  • Breakthrough cancer pain (morphine, alfentanil)
  • Erectile dysfunction (apomorphine)
  • Motion sickness/ anti nausea (scopalamine)
34
Q

What are some patient factors affecting nasal absorption?

A
  • Acceptable to patient. Is it comfortable and non invasive? To increase compliance. Is it a simple dosage form? e.g. drops or sprays?
  • Variability of dosing. High MWt v.s Low MWt
  • Disease. Has the patient got a common cold or inflammation?
35
Q

Why is it difficult to deliver drugs to the brain?

A

Because of the BBB. The cerebral microvascular endothelium is not leaky and it possess tight junctions.

36
Q

What are the slow and fast pathways of the brain?

A

Slow - Olfactory nerve pathway (intraaxonal transport to olfactory bulb via endocytosis, then goes to CNS; BBB is bypassed)
Fast - Epithelial pathway (other route other than olfactory neurone - paracellular)

PY352 (25 decks)

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