We, humans have relatively simple noses as primary
function is respiration (breathing). But, other animals, especially mammals
have complex noses adapted for their primary function i.e., olfaction
(smelling).
Human
nasal cavity has large surface area and is highly vascularised. So, the drugs
get absorbed through this rich network of blood vessels and enter directly into
the blood stream. This means to say that, faster onset of action. Thus, nasal
cavity can be exploited as a route of entry of drugs into the systemic
circulation (blood) of the human body; mainly for those compounds, which cannot
be given orally.
Nasal drug delivery system is a rapidly expanding field- a parallel expansion to
biotechnology.This has caused significant increase in the production of
therapeutic peptides and proteins,globally.
Liquids, powders and gels are being used to
deliver drug via this route. It includes microspheres, liposomes and
nanoparticles. Microsphere technology is a specialized system used for
designing nasal products.This provides a prolonged contact of drug with the
nasal mucosal layer and thus enhances absorption and bioavailability.
Some compounds like Fusidic acid
derivatives are used in the studies of absorption of insulin,growth hormones
etc. which is under ‘clinical trials’ phase.
Drugs
which are given during allergic rhinitis,nasal congestion,infections account
for over 75% of current nasal drug delivery market($3000
million/annum).Systemically-acting drugs,about 30%.Intranasal delivery is
employed lately for the treatment of acute pain relief,vit-B12 deficiency,
migraine,smoking cessation, etc.
The intranasal route, in other words can become a
promising alternative to the intravenous route(injectables) in the coming
days.Thus there’ll be a development of safe and efficacious formulations
for simple, painless and long-term
therapies.
An idealist is one who, on noticing that roses smell better than a cabbage, concludes that it will also make better soup.
H. L. Mencken
H. L. Mencken
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