Nasal drug delivery Flashcards Preview

RMS > Nasal drug delivery > Flashcards

Flashcards in Nasal drug delivery Deck (21):
1

Why deliver drugs to the nasal cavity?

- local drug delivery
allergic rhinitis, congestion, infection

- systemic absorption
diabetes insipidius, migraine, prostate cancer, osteoporosis

nasal drug delivery results in a faster systemic absorption than oral drug delivery

to deliver peptides

2

Advantages of nasal drug delivery

- high vascularisation due to blood supply close to surface of mucosa
- accessbility
- ease of admin
- reduced first pass metabolism
- low metabolic activity compared to GI tract
- large surface area

3

Disadvantages of nasal drug delivery

- low pH may lead to irritancy- SIDE EFFECTS
- limited dose
- patients may find it difficult to administer- REPRODUCIBILITY
- reduced absorption due to mucus- more than in lungs
- LOW residence time

4

What is the nasal cavity?

the upper airways

5

Function of the nose

- olfaction
- air conditioning due to high vascularisation which humidifies the air

does not recieve drugs for systemic absorption

6

Structure of the nose

- length of nasal cavity is 12-14cm
- volume holds 10-14cm3
- divided by the nasal septum
- vestibule 1.5cm long vibrasse
- ends in the internal ostium (nasal valve) which is the narrowest part of the airway

7

Fate of particles delivered to the nose

>10 micrometres is filtered by the vibrasse
5-10 micrometres deposits in the nasal passages and is subject to mucociliary clearance
<2 micrometres passes through to the lungs

8

Structure of the respiratory epithelium

ciliated columnar cells
goblet cells
non-ciliated columnar cells
basal cells

9

Mucus

- from serous glands and goblet cells
- form viscous gels due to high molecular weight mucins and ability to form disulphide bridges

function: air conditioning and to trap things

10

Composition of mucus

water 90-95%
mucins 0.5-5% (responsible for gel like structure)
lipids 2-3%
salts 1-2%

11

Mucociliary clearance

cilia have hooks which beat in a coordinated manner

continuously move foreign material to the back of the throat

low return stroke so continuously push waft forward

12

Types of preparations used in nasal drug formulations?

for topical therapy and systemic absorption in prescription medicines

otc

non- drug preparations

13

devices used to administer nasal drug formulations

drops- easiest- must rest head on one side for 30 seconds

sprays

powders- less popular but may be used to administer peptides that are usually unstable

gels
ointments- difficult to get into nasal cavity

14

Formulation factors

drug concentration

dose

formulation pH- affects solubility

formulation osmolarity

physical form

volume

15

peptide delivery

alternative to oral dosing for peptide hormones

inverse relationship between absorption and size (max 14 amino acids)

peptidase enzymes limit bioavailability

16

Name some intranasal peptides < 10 amino acids

- desmopressin spray and drops

- buserelinspray

17

Name some intranasal peptides > 10 amino acids

- salmon calcitonin nasal spray

1% bioavailability

32 amino acids
used for osteoporosis

- insulin

18

peptide and protein degrading enzymes

carboxypeptidase
aminopeptidase
endopeptidase
protease

19

What promotes nasal peptide and protein absorption by increasing permability

surfactants and bile salts

20

what promotes peptide absorption by making tight junctions open up a bit

chelating agents
fatty acids

21

what other excipients promote nasal peptide and protein absorption?

- enzyme inhibitors- less presystemic loss to metabolism

- bioadhesive delivery systems --> longer retention