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Can anyone provide a computer program (Excel, etc) to calculate human
clearance from human microsomal experiments, where binding was and was
NOT studied with the microsomes? I presume one would simply enter
T-1/2 and microsomal protein concentration, and where binding was
studied to microsomes, this information as well.
Thanks in advance for your consideration.
Harold Boxenbaum, Ph.D.
Pharmacokinetic Consultant
Arishel Inc.
14621 Settlers Landing Way
North Potomac, MD 20878-4305
Website: www.arishel.com
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The following message was posted to: PharmPK
Dear Harold:
This might help (see some of the David Greenblatt publications)
I don't think binding to microsomes is an issue in this calculations,
1. Human Clearance = Q*Km/Vmax where Q hepatic perfusion rate, KM and
Vmax obtained from human microsomes.
2. If you don't have any of these values from humans then you have to
apply for allometric scaling.
If you need a consultant on allometric scaling my mentor Dr. Harold
Boxenbaum might help you!!!!!!! (Big Grin)
Cheers;
Prasad Tata
Saint Louis, MO
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The following message was posted to: PharmPK
Dear Prasad,
You wrote:
> 1. Human Clearance = Q*Km/Vmax where Q hepatic perfusion rate,
> KM and Vmax obtained from human microsomes.
I don't understand. The right-hand part would yield a dimensionless
value (if Q in volume/time, Km in amount/volume and Vmax in
amount/time), or in some strange dimension (if Q and Vmax are
expressed per gram liver, or per mg protein of whatever).
best regards,
Hans Proost
Johannes H. Proost
Dept. of Pharmacokinetics and Drug Delivery
University Centre for Pharmacy
Antonius Deusinglaan 1
9713 AV Groningen, The Netherlands
Email: j.h.proost.aaa.rug.nl
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