- On 15 Jun 2006 at 07:36:26, Kate Roupe (karoupe.aaa.yahoo.com) sent the message

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Dear All,

I am looking for the appropriate equation to calculate clearance. The

subjects are to be administered a bolus IV dose (8 mg/kg or 16 mg/kg)

followed by a continuous infusion (47.5 mg/kg/12 hr or 32 mg/kg/12).

Thanks,

Kathryn Roupe, Ph.D.

Senior Pharmacokineticist - On 16 Jun 2006 at 07:11:30, "ogwal sidney" (sidneyogwal.-a-.hotmail.com) sent the message

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The following message was posted to: PharmPK

s.o.o

Check in a first course in Pharmacpkinetics and Biopharmaceutics by

Proff. David Bourne

[Thanks Sidney, that would be http://www.boomer.org/c/p4/ or http://

www.boomer.org/c/p3/

Actually it's a little more complicated. Do you start the infusion at

the same time as the bolus is given? Is there a delay? After just a

bolus dose, clearance can be calculated as Dose/AUC (http://

www.boomer.org/c/p4/c04/c0410.html). During an infusion at steady

state, clearance can be calculated as Infusion Rate/Cp(ss) (http://

www.boomer.org/c/p4/c06/c0602.html). If your objective is to dose to

steady state using a bolus/infusion regimen then the second equation

may be suitable once you have verified that steady state has been

achieved (http://www.boomer.org/c/p4/c06/c0604.html). Otherwise, if

you have enough suitable data points modeling the data in terms of V

and CL should work - db] - On 16 Jun 2006 at 18:33:52, "Shawn D. Spencer" (shawn.spencer.-a-.famu.edu) sent the message

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Kate,

Your question is suprisingly odd... almost as if part of your

question is missing. Does this drug undergo (or is expected to

undergo) nonlinear disposition processes, which is why you mentioned

the dose regimen? One assumes you have limited data (i.e. no iv

bolus regimens), and if so, you need only your concentration at

steady state to arrive at a clinical estimate for clearance. It is

not likely you have clinical data without a rough estimate of your

half-life, and so wait at least 5 half-lives use the concentration to

arrive at a preliminary estimate of clearance. Again, one assumes

there is more to the question.

Keep in touch..

-Shawn

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