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The following message was posted to: PharmPK
Dear friends
Drug is poorly water soluble and highly lipophilic. The LD 50 value
is 8000 mg/kg in rats (oral route). The effective dose for cattle's
is 2.5mg/kg (I.M route) and there is no information about the dose in
oral route.
Based on the above information can any one help to clarify the
following?
I need to conduct the pharmacokinetic study in rabbits. The
Formulation is emulsion and the route of administration is oral. At
which dose I need to carry out the PK study. I didn't find any dose
conversion formula for cattle to rabbits.
Your valuable comments are appreciable
Thanks in advance
Venkatesh
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Venkatesh,
Please see the references below. We have determined that there is no
a priori way of doing what you propose. Yes, a few drugs do scale,
but they are the exceptions, not the rule for species outside of
those used for human scaling (rodent, dog, nonhuman primate). This
is particularly true when outside of the weight range used for human
drug scaling.
Please contact me if you have more questions.
M. Martinez, I. Mahmood, & R.P. Hunter (2006) Interspecies allometric
scaling: prediction of clearance in large animal species: Part II:
mathematical considerations. J. vet. Pharmacol. Therap., 29, 425-432.
I. Mahmood, M. Martinez, & R.P. Hunter (2006) Interspecies allometric
scaling. Part I: prediction of clearance in large animals. J. vet.
Pharmacol. Therap., 29, 415-423.
Rob Hunter, M.S., Ph.D.
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The following message was posted to: PharmPK
Hi,
I think this experience formula table maybe usefull to you!
type adult dog cat&rabbit mice
dose 1mg/kg *2 *3 *12
" * " means multiply
Good luck!
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The following message was posted to: PharmPK
Dear Venktesh
You can find your answer yourself if you ask few questions to yourself
What is dose regimen in therapeutic setting if info is available?
Can rabbits be administered 2.5 mg/kg orally safely? (this question
only you can answer as you know better about the compound)
Is PK data available for rats and cattle?
Why am I carrying PK in rabbits?
And many more,
Combining answers to these will lead you to some judgment about
designing the experiment. In any case I believe the chances are more
that you will have to do many dose levels to achieve your objectives
of conducting PK experiments in rabbits
with best regards
Dr.Prashant
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Dear All
On which basis it has to be decided whether plasma or serum matrix
has to be use for estimation of drug in blood.
If any reference is there well and good.
Thank you one and all.
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