Registration for a live webinar on 'Innovative Vaccines and Viral Pathogenesis: Insights from Recent Monkeypox (Mpox) Research' is now open.
See webinar detailsWe noted you are experiencing viewing problems
-
Check with your IT department that JWPlatform, JWPlayer and Amazon AWS & CloudFront are not being blocked by your network. The relevant domains are *.jwplatform.com, *.jwpsrv.com, *.jwpcdn.com, jwpltx.com, jwpsrv.a.ssl.fastly.net, *.amazonaws.com and *.cloudfront.net. The relevant ports are 80 and 443.
-
Check the following talk links to see which ones work correctly:
Auto Mode
HTTP Progressive Download Send us your results from the above test links at access@hstalks.com and we will contact you with further advice on troubleshooting your viewing problems. -
No luck yet? More tips for troubleshooting viewing issues
-
Contact HST Support access@hstalks.com
-
Please review our troubleshooting guide for tips and advice on resolving your viewing problems.
-
For additional help, please don't hesitate to contact HST support access@hstalks.com
We hope you have enjoyed this limited-length demo
This is a limited length demo talk; you may
login or
review methods of
obtaining more access.
Printable Handouts
Navigable Slide Index
- Introduction
- Why this topic?
- Bioavailability: definitions
- Absorption
- Pre-absorption
- Absorption: mechanisms to cross cell membranes
- Absorption: mechanisms and clinical relevance
- Absorption: first-pass mechanism (clinical relevance)
- Distribution volume: definition
- Distribution: definition and pattern
- Distribution: clinical determinants
- Distribution: clinical relevance
- Take home messages
Topics Covered
- Bioavailability, absorption and distribution
- Pre-absorption
- Mechanisms to cross cell membranes
- First-pass mechanism
- The effect of drug-drug interactions and drug-food interactions
- Distribution volume
Talk Citation
Allegaert, K. (2024, September 30). Bioavailability, absorption and distribution [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved November 14, 2024, from https://doi.org/10.69645/SQFQ7677.Export Citation (RIS)
Publication History
Financial Disclosures
- There are no commercial/financial matters to disclose. However, off label use of medicines is discussed.
Other Talks in the Series: Key Concepts: Fundamentals of Pharmacology
Transcript
Please wait while the transcript is being prepared...
0:00
Welcome to this short
lecture on bioavailability,
absorption, and distribution.
I'm Karel Allegaert,
Clinical Pharmacologist
working at KU Leuven
in Belgium as well as
Erasmus University of
Rotterdam in the Netherlands.
0:17
Why are we discussing
this topic?
Well, it is because absorption
as well as distribution
are two of the four parameters
crucial to determine
pharmacokinetics.
Absorption, distribution,
metabolism,
and excretion will drive the
concentration/time profile.
We will focus on these
first two parameters in
this short lecture and
other information on
metabolism and excretion will
be provided in another lecture.
0:46
Let's go first to
some definitions.
If we consider bioavailability
commonly used with a big F,
it relates to the fraction
of an administered drug that
gains access to the
systemic circulation,
so by definition, it is
between zero and 100.
Absolute values refer to
the area under the curve
obtained after a given dose is
provided by intravenous route.
Relative bioavailability
refers to when you compare
two different formulations or
two different routes
of administration,
for instance, oral tablet
versus oral syrup,
or oral tablet versus
subcutaneous administration.
1:28
Absorption in itself is by
definition, the
passage of a drug
from its site of administration
to its site of action
and to do so, it will have
to cross cell membranes.
Except for IV administration,
the drug will have to be
transported from the initial
site of the administration,
for instance,
subcutaneous, oral,
sublingual, and will
have to make it
into the systemic/blood
circulation.
However, we should realize that
the systemic circulation
itself is not always the site
of action for a given
drug for instance
for analgesic or
seizures it's in general
the central nervous
system that you target.
For chemotherapy, it
could be in the blood
if it is, for instance, leukemia
but it can also be
located in other tissues.
For instance, for infections,
if you have a
subcutaneous infection,
it's nice to have an
antibiotic in your circulation
but it will have to make it to
the subcutaneous tissues
to be effective.