nasal delivery

Question 1

What are the primary therapeutic uses of nasal drug delivery?

Answer 1

1. Localized effect, rhinitis + nasal congestion
2. systemic effect, pain + smoking cessation
3. vaccine delivery, influenza
4. direct nose-to-brain delivery.

Question 2

What is the role of the turbinates in nasal drug delivery? also describe the anatomy of them

Answer 2

1.They increase surface area, facilitate drug deposition, and have a rich blood supply for absorption.
2. main site of drug absorption
3. contain goblet cells that cover epthelium.

anatomy: inferior,niddle,superior
turbulent air flow
epitheilial cells and giblet cells

Question 3

What are the two main pathways for nasal drug transportation?

Answer 3

1. Transcellular diffusion (lipophilic drugs, mainly passive diffusion through rich membranes of epithelial cells)
2. paracellular diffusion (small hydrophilic drugs, rate proportional to molecular size).

Question 4

What factors affect drug absorption in nasal delivery?

Answer 4

1. Mucociliary clearance, ‘conveyor belt’, causes limited contact time
2. mucus layer, acts as a barrier to drugs
3. enzymatic activity, metabolises
4. epithelial barrier

Question 5

Name strategies to improve nasal drug absorption.

Answer 5

1. Increase nasal resistance time using Mucoadhesive polymers
2. enzyme inhibitors, these prevent hydrolysis and improves permeability
3. permeation enhancers, alter epithelium
4. solubility enhancers, changes molecular form.

Question 6

What is mucoadhesion in nasal drug delivery? give an example

Answer 6

The attachment of a drug carrier to the mucus layer to extend contact time.
required to combat mucociliary clearance
can be physical/chemical bonding
eg; liquids, gels,powders

Question 7

explain how bioadhesion works

Answer 7

two biological materials are held together by interfacial forces (occurs in nasal epithial surface)

Question 8

Describe the two stages of mucoadhesion.

Answer 8

1. Contact stage (initial attachment)
2. consolidation stage (bond formation between mucus and polymer). + (formation of chemical bonds like VDW, H bonding etc.)

Question 9

What are some formulation considerations for nasal drug products?

Answer 9

1. physiochemical properties: Solubility, pH, molecular size,
   2.stability,
2. minimising excipients.
3. particle size distribution

Question 10

What are the advantages of nasal drug delivery?

Answer 10

1. good compliance(Non-invasive)
2. rapid effect
3. avoids first-pass metabolism
4. lower doses are required.
5. manufacturing cost low
6. manages chronic disorders

Question 11

What are some disadvantages of nasal drug delivery?

Answer 11

1. Limited volume capacity
2. mucociliary clearance
3. enzymatic activity/metabolism
4. low permeability for hydrophilic drugs
5. potential drug instability.
6. short absorption time
7. rebound congestion

Question 12

outline and explain five excipients used in the manufacture of nasal dosage form

Answer 12

1. vehicle; medium that drug is dissolved in
2. surfactant; lowers surface tension with drug and liquids
3. viscosity enhancer; increases resistance time in nasal cavity
4. flavouring; improves tastes/flavour
5. buffer; ensures pH stability