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Dear colleagues
I would appreciate information concerning atenolol absorption in the
human g.i. tube. In particular, the areas (gastric or intestinal) where
main absorption takes place, and correlations (if any) with PK and
lipophobicity.
Thank you
Carlos Montuenga
Madrid, Spain
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The following message was posted to: PharmPK
Dear Carlos,
Atenolol can be classified as Class III drug, high solubility and low
permeability,based on the biopharmaceutic classification system and the
absorption mechanism is mostly through passive paracellular transport
mechanism ( It is usually used as a marker in Caco-2 permeability
studies to predict the type of absorption mechanism involved).The
absorption is a bit more from the distal part of small intestine.But
well absorbed all through the intestinal length.( as a very fact that
absorption is not affected by physiological behaviour of the stomach :
fed or fasting mode)
On the lipophilicity front, with increased Log P the permeability of
the compound will increase ,this may affect the Pharmacokinetics in may
ways like volume of distribution and protien binding and so also
elimination half life.
Hope this suffices the purpose of querry.
Kind regards,
Pradeep S. Bhadauria
Ranbaxy Research Laboratories
INDIA.
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Dear Carlos
Lipophilicity behavior of atenolol has been extensively determined in
the
following paper (see also references therein). In addition relationships
between pk properties and lipophilicity of beta-blockers have been
looked
for.
Regards
Giulia Caron
G.Caron, G.Steyaert, A.Pagliara, F.Reymond, P.Crivori, P.Gaillard,
P.A.Carrupt, A.Avdeef, J.E.Comer, K.J.Box, H.H.Girault, and B.Testa.
Structure-lipophilicity relationships of neutral and protonated
b?blockers.
Part I. Intra- and Intermolecular Effects in Isotropic Systems. Helv.
Chim. Acta 82: 1211?1222 (1999).
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annon pls.
Carlos,
Given that Atenolol is a Class III drug, it does present some
difficulty. We have planned a two day conference to help people deal
with these types of challenges. In fact, there is emphasis placed in
our agenda specifically on dealing with Class III drugs and how to use
the BCS to facilitate working with these drugs. Check out the program:
http://www.barnettinternational.com/pdfs/BI429PROD.pdf
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At 05:26 AM 11/25/02, pradeepbhadauria.-a-.sify.com wrote:
On the lipophilicity front, with increased Log P the permeability of
the compound will increase ,this may affect the Pharmacokinetics in may
ways like volume of distribution and protien binding and so also
elimination half life.
The theory that increased logP = increased permeability is not at all
reliable. For about 400 compounds run in high quality MDCK cell
culture, the correlation between logP and Papp was quite poor (R^2 ~
0.1). Many compounds with high logP had lower Papp than many with low
logP.
Permeability is much more complex than lipophilicity alone can predict.
Walt Woltosz
Chairman & CEO
Simulations Plus, Inc. (SIMU)
1220 W. Avenue J
Lancaster, CA 93534-2902
U.S.A.
http://www.simulations-plus.com
E-mail: walt.aaa.simulations-plus.com
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