Nasal drug delivery Flashcards
nasal drug delivery is the fastest growing drug delivery system, true or false
true
the nasal cavity extends from where to where
the nostrils to the nasopharynx
the nasal cavity is a poorly vascularised system, rich in secretory cells, true or false
false
it is a** highly ** vascularised system, rich in secretory cells
which region of the nasal cavity is located at it’s roof
the olfactory region
name some types of cells that we can find in the nasal cavity
ciliated cells
goblet cells
the main regions of the nasal cavity
olfactory region
respiratory region
vestibular region
order the regions of the nasal cavity based on surface area
respiratory region has the highest surface area, then the olfactory region, then the vestibular region
note that the respiratory region is highly vascularised
there is direct access to the brain via the olfactory region, true or false
true
Olfactory region is the only part in the whole body where CNS is in contact with the peripheral environment
the significance of a large surface area in nasal drug delivery
rapid drug absorption and systemic delivery
improved CNS drug delivery
local drug delivery for respiratory conditions
(the avoidance of first pass metabolism in nasal drug delivery is key)
describe mucocilliary clearance
Mucociliary clearance, also known as the mucociliary escalator, is a vital defense mechanism of the respiratory system that removes inhaled particles and pathogens by trapping them in a layer of mucus and then propelling them towards the oropharynx for removal
could also say Mucociliary clearance is a primary innate defense in the upper and lower airways. Pathogens, including viruses, are trapped in the mucus layer and then removed from the airways by motile cilia. Viruses can target this mucociliary defense through various mechanisms.
when is mucocilliary clearance compromised
if there are abnormalities with the cilia, mucus or periciliary fluid
what happens when there is too much secretion of periciliary fluid
what happens when there is too little secretion of periciliary fluid
Too much secretion of periciliary fluid → complete cover of the cilia
Too low secretion of periciliary fluid → cilia tangled in the mucus gel
The periciliary fluid, also known as the sol layer, is a thin, watery layer of fluid that lies beneath the mucus layer in the respiratory tract, including the nasal cavity and lower airways. It plays a crucial role in mucociliary clearance, ensuring efficient removal of inhaled particles, pathogens, and excess mucus.
the role of the cilia in the nasal cavity
Hairlike structures called cilia line the mucous membrane and move the particles trapped in the mucus out of the nose. so basically the cilia helps filter the air in that enters the nose
the periciliary fluid is primarily found in the respiratory region of the nasal cavity, true or false
true
Cystic fibrosis, asthma, chronic bronchitis, COPD or acute RDS might cause an increase in the viscoelasticity of the nasal mucus, true or false?
if this happens, how would that affect MCC (mucociliary
clearance.)
true
it will slow down mucocilliary clearance
name some protective substances secreted by the nose against pathogens and what they do
IgA , to prevent attachment of bacteria to the mucosa
Lysozymes, to protect the cells against infections by attacking cell walls of microorganisms.
the average pH of nasal secretions in adults and in children
5.5-6.5
5.0-6.7
nasal secretions become more acidic in conditions like acute rhinitis, and acute sinusitis, true or false
false
they become more alkaline
some examples of nasal secretions
water
immunoglobulins
electrolytes
proteins
salts
WBCs…etc
which nasal secretion(protein) acts as an antibacterial and what happens to it’s activity in alkaline pH
lysozymes
it’s activity is dimished
the olfactory mucosa is in direct contact with the brain and CSF, true or false
true
i.e medications absorbed across the olfactory mucosa directly enter the brain
describe the nose-brain pathway
The “nose-to-brain pathway” refers to the direct route from the nasal cavity to the brain, bypassing the blood-brain barrier (BBB), primarily through the olfactory and trigeminal nerve pathways, which is being explored for drug delivery and other therapeutic applications.
name some advantages of nasal drug delivery
Large SA (~160 cm2) available for drug absorption.
High blood vascularity (rich blood supply) → rapid absorption to the systemic circulation + rapid onset of action.
Non-invasive delivery route.
Ease of administration.
Enzymatic activity in the nasal cavity < the GIT → delivery via the nose appropriate for many drugs especially peptides.
A good alternative to GIT for patients who have N&V or swallowing difficulties, for drugs that undergo extensive first pass effect or have detrimental effects on the GIT
epithelium.
What are the two primary routes of drug absorption after nasal administration?
Systemic circulation (blood) via the nasal epithelium.
Direct transport to the brain via the olfactory region and cerebrospinal fluid (CSF).
How does nasal drug delivery bypass the first-pass effect?
Drugs administered nasally avoid gastrointestinal (GI) metabolism and hepatic first-pass degradation, allowing for higher bioavailability.
What role does the olfactory region play in nasal drug absorption?
The olfactory region provides a direct pathway to the brain via the cerebrospinal fluid (CSF), enabling rapid drug delivery to the central nervous system (CNS).
What are the major factors limiting drug absorption through the nasal cavity?
Mucociliary clearance (MCC), enzymatic degradation, and barriers like the blood-brain barrier (BBB) for CNS-targeted drugs
