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Please could anyone help with the following;
1) Could anyone suggest possible explanations for a finding of Vz
much greater than Vss following iv bolus dose administration, apart
from the possibility that the terminal phase represents distribution
rather than elimination?
2) What is the likelihood of "peripheral compartment" elimination of
a large molecule such as a monoclonal antibody?
Thanks
Alan
HUNTINGDON LIFE.SCIENCES LIMITED
http://www.huntingdon.com
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The following message was posted to: PharmPK
Dear Alan,
For the one-compartment model only, Vz equals the volume of distribution
at steady-state, Vss. For all other cases, variation in other parameters
e.g. clearance will affect the parameter Vz. Therefore, Vz does not
provide independent physiologically meaningful information by itself. It
appears from your message that you are dealing with a 2-compartment
model (at the least). Hence I guess I do not understand why you are
interested in determining Vz.
Regards,
Joga Gobburu
Pharmacometrics,
CDER, FDA.
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The following message was posted to: PharmPK
Mabs are not "eliminated" from prephirial compartments but are
sequestered in such a manner to appear to be eliminated. See:
Webster WB, Harwood SJ, Carroll RG, Morrissey MA. Pharmacokinetics of
111In-Labeled B72.3 Monoclonal Antibody in Colorectal Cancer Patients.
The Journal of Nuclear Medicine 1992; 33: 498-504.
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