Back to the Top
I have queries regarding the permeability assay performed by PAMPA and Caco-2 techniques:
1. For the PAMPA is it necessary to have same pH in both the donor and acceptor wells
while different pH in both the donor and acceptor for Caco-2. Why is it and on what
factors does it depends?
2. If I want to compare permeability data from PAMPA and Caco-2 for a drug candidate, the
time of incubation should be same or it may vary in these techniques? What are the
determining factors?
-
Chetan
Back to the Top
The following message was posted to: PharmPK
Hi Chetan
PAMPA is a passive permeability assay in absence of transporters. It
serves as a screening tool for estimating permeab of compounds with
passive transcellular diffusion mech.
Caco2 on the other hand expresses diff transporters and very low levels
of CYP enzymes. This is physiologically more closer to human intestinal
enterocytes.
The incubation period for PAMPA depends on supplier requirements 4hr in
general. For Caco2 generally the incubation is upto 2h as cells may die
if assay is prolonged further.
Generally we don't compare headon the perm values obtained from the two
assays.
Comments from experts are welcomed.
Tausif Ahmed, PhD.
Asst. Dir.
Piramal Healthcare
Mumbai, India
Back to the Top
Dear Chetan,
Answer to your first question: it is not necessary to have the same pH
in apical and basolateral sides in PAMPA, rather to simulation the GI it
is preferable to have different pH solutions in the apical, however the
basolateral will be the physiological pH. Your second question has been
answered by Dr. Tausif.
Pratima
|
Want to post a follow-up message on this topic?
If this link does not work with your browser send a follow-up message to PharmPK@boomer.org with "Permeability - PAMPA vs Caco-2" as the subject | Support PharmPK by using the |
Copyright 1995-2011 David W. A. Bourne (david@boomer.org)