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The following message was posted to: PharmPK
Can anybody offer suggestion on:
1. Should plasma samples be kept frozen or if they can stay at room
temperature prior to bioanalysis? We're trying to investigate the
best way
to handle blood samples for PK analysis. Reason for asking, when
samples
are thawed for bioanalysis the samples are clotting. Any suggestions
would
be helpful.
Thanks in advance!
Leslie Jones
LESLIE D. JONES, ALAT
RESEARCH SCIENTIST II
ICAGEN, INC
4222 EMPEROR BLVD.
STE. 350
DURHAM, NC 27703
PHONE: 919-941-5206 EXT. 553
LAB PHONE: 919-541-7153
FAX: 919-941-0813
[Would an anti-coagulant help? - db]
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The following message was posted to: PharmPK
Dear Jones,
You asked, if plasma samples should be frozen or stored at room
temperature
prior to bioanalysis.
Actually either way is fine PROVIDED, you have shown previously during
Bioanlytical method development that plasma samples spiked with your
drug of
interest are stable for a minimum of period comparable to the usual lag
period between PK study and bioanalysis.
Hope it helps.
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Leslie,
I don't understand the question really. I know of blood (platelets)
clotting but not of plasma clotting. Do you mean that you see some
(protein) precipitate?
We collect plasma with heparin or EDTA and freeze pooled plasma at
-80*C without problems.
Regards,
Frederik Pruijn
Frederik B. Pruijn PhD MSc (Senior Research Fellow)
Experimental Oncology Group
Auckland Cancer Society Research Centre
Faculty of Medical and Health Sciences
The University of Auckland
Private Bag 92019
Auckland
New Zealand
Phone: +64-9-3737 599 x86939 or x86090
Fax: +64-9-3737 571
E-mail: f.pruijn.-a-.auckland.ac.nz
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Dear Leslie,
Regarding the temperature conditions required for the plasma for PK
study refer the following article. It might be useful for you.
Tadakazu Tokumura et al, (2005) Stability of Spiranolactone in Rat
Plasma : Strict Temperature Control of Blood Samples and plasma
samples is required in rat pharmacokinetic studuies, Biol, Pharm,
Bull, (28) 6, 1126-1128.
all the best,
Rajesh. O.S.
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The following message was posted to: PharmPK
Dear Leslie,
how do you prepare plasma?
This problems are common in serum samples, maybe the anticoagulant is
not enough.
Regards
Dr Roberto Conti
Sigma-Tau
Dep. of Endocrinology and Metabolism
00040 pomezia, Roma
Phone: +39-06-91393322
Fax: +39-06-91393988
e-mail. roberto.conti.-a-.sigma-tau.it
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The following message was posted to: PharmPK
Hello Leslie,
I was curious like Frederick about whether the samples were plasma,
serum,
or whole blood. Sorry if I come across as dense here. I have used a
validated GC/MS method for extracting drug from rat plasma samples
that had
been stored at -180 C. The blood samples were spun down and the drug
was
extracted from the plasma which was stored frozen prior to analysis.
The
analysis was based upon the same method used to analyze blood plasma
for the
standard employment drug screen. Hope this information is of some
use to
you.
All the best,
James Ladd
James Ladd
Scientist Erimos Pharmaceuticals
840 main campus Drive suite 3700
Raleigh, NC 27606
jladd.-a-.erimos.com tel: +1 (9198215204) EXT2816
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The following message was posted to: PharmPK
Hi,
Papers have been published regarding the reason of
clotting. the suggestion is to use EDTA but not
heparin as an anticoagulant.
Hepe this can help.
Xiaodong
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Hi Leslie what you mean by clotting is probably just protein globules/
precipitates . This is normally seen if the plasma has been stored
for a long time. How long ago were the plasma stored? You can
recentrifuge the plasma samples and then use the supernatant for your
analysis.
Indranil Bhattacharya
Ph.D candidate
Dept. of Pharmaceutical Sciences
State University of New York at Buffalo
Usa
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The following message was posted to: PharmPK
Hi,
It sounds to me that what you analyzed is serum matrix
not plasma.
Thanks.
Xiaodong
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