Lecture 8 Flashcards
What are the advantages of nasal drug delivery?
Nasal drug delivery is non-invasive, offers rapid absorption, has a large surface area, and connects to systemic circulation.
Why is nasal drug delivery potentially useful for neurological disorders?
Nasal drug delivery bypasses the blood–brain barrier, providing direct pathways to the CNS, making it a potential route for treating neurological disorders where most drugs cannot cross the blood–brain barrier effectively
What are the three main pathways for drug absorption in the nasal cavity? (And the additional one)
- Transcellular route: Passive diffusion through the cells of the nasal epithelium.
- Paracellular route: Transport between cells via tight junctions.
- Olfactory pathway: Direct access to the CNS via the neurons
The trigeminal pathway provides another route
What are the disadvantages of nasal drug delivery?
Disadvantages include the nose’s natural cleaning mechanism removing the drug, mucosal enzymes degrading drugs, and the limited volume of drug that can be administered
What types of formulations are used for nasal drug delivery?
- Solutions: Simple to manufacture but can have stability issues.
- Suspensions: Useful for poorly soluble drugs.
- Dry powders: More stable than solutions.
- Semi-solids/gels: Provide prolonged contact time with nasal mucosa.
- Emulsions: Enhance drug solubility and absorption.
What are permeation enhancers and mucoadhesive agents in nasal drug delivery?
Permeation enhancers temporarily disrupt the nasal epithelium to improve drug absorption. Mucoadhesive agents increase residence time in the nasal cavity by adhering to the mucus layer covering the nasal epithelium.
What are some common excipients used in nasal drug formulations?
Excipients like solvents (water), preservatives, and buffers improve stability, efficacy, and patient acceptability.
What is chitosan and how is it used in nasal drug delivery?
Chitosan is a natural polymer derived from chitin, used as both a permeation enhancer and mucoadhesive agent. It can improve drug solubility, bind to the mucosal surface, open tight junctions, and is non-toxic.
