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I have been through the archives on this topic and would like
clarification on the volume of blood that can be withdrawn from a rat.
I am attempting to determine the PK of a drug from a controlled release
formulation which is implanted s.c. I am using JVC rats (275 g)and
will be sampling as follows:
0, 15, 30, 1, 6, 12, 24, 48, 72, 96 and 120 h. I will withdraw ~ 0.25
ml of blood per time point and replace with an equivalent volume of
saline. From the previous messages it seems that you can not withdraw
more than 10% of the blood volume in 24 hrs, however since I am
sampling over 5 days would this sampling schedule be appropriate. I
need to ensure that the rats will be healthy during the 5 day period.
How long does it take for rats to regenerate RBC?
Thanks
Anita
Anita Lalloo
Ernest Mario School of Pharmacy
160 Frelinghuysen Road
Piscataway
NJ 08854
Tel: 732 445 3831 ext 225 (W)
908 526 8875 (H)
732 445 3134 (F)
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The following message was posted to: PharmPK
Dear Anita
I do not see any reason to worry. You are withdrawing just o.25 ml
out of about 13 ml blood each time (5% of BW). Replacemnet of RBCs
is almost a continuous process. Even if do not replace blood
volume by saline it would not matter in my opinion under the
circumstances detailed by you.
Thanks and Regards
Dr. Prashant
Ph.D.
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The following message was posted to: PharmPK
hello,
here are the limit volume and recovery method from Good practice source
:
EFPIA/ECVAM (june 1999)
% circulating blood volume removed in 24h : 7.5% recovery period
1 week
% circulating blood volume removed in 24h : 10% recovery period 2
weeks
% circulating blood volume removed in 24h : 15% recovery period 4
weeks
20% within 24 hours of euthanasia
Ex for rat weighing 250 g total blood vol : 16 ml
7.5% 1.2ml
10% 1.6 ml
15% 2.4ml
20% 3.2ml
Hope this can hellp
Eric MAGNAN
IPSEN PHARMA BIOTECH
Dpt Contrôle Qualité/Quality control Dept
Service Pharmacologie/Pharmacology Unit
Tel : 33 (0)4 94 10 76 74 Fax: 33 (0)4 94 10 76 79
eric.magnan.aaa.ipsen.com
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The following message was posted to: PharmPK
RBC survival time in rats is approx. 50 days
After withdrawl of 10% of total blood vol. there should
be a recovery period of approx. 2 weeks
best regards
Manfred Zimmer
Manfred Zimmer
Aventis Pharma Deutschland GmbH
DI&A, LO, DMPK
in-vivo PK / Special Analytics (QWBA)
65933 Frankfurt/Main
Industriepark Höchst, G 876, R225
Phone: +49 (69) 305-43661
e-mail: Manfred.Zimmer.-at-.aventis.com
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The following message was posted to: PharmPK
Dear Manfred
You wrote
RBC survival time in rats is approx. 50 days
> After withdrawl of 10% of total blood vol. there should
> be a recovery period of approx. 2 weeks
However the replacing of RBCs is not dependant (directly) on the
half life of RBC but how fast bone marrow cells mature. Cell
depletion in blood would activate someway the process of
maturation of bone marrow cells (at a fasterrate than normal). I
believe a veternary pathologist wouldbe able to tell this more
precisely.
Thanks and regards
Dr. Prashant
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