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I know this is an old thread, but I want to reopen it.
http://www.boomer.org/pkin/PK07/PK2007522.html
For collection of human gemcitabine blood samples, we want to prepare
heparin tubes in the manner that Dr. Beumer has suggested - THU
solution, injected into Vacutainer tubes in small volumes using TB
syringes. However, we are concerned with the stability of this
solution when stored at room temperature after preparing such tubes.
Does anyone have any information on the stability of the THU at room
temperature in heparin tubes? At -20C, protected from light? I would
ask sites to make up fresh THU solution and pre-spike standard heparin
tubes if I were confident that they could do it without trouble, but
we want to avoid that.
Any comments on this?
Thanks,
Burgess
Burgess Freeman, Pharm.D.
Sr. Research Scientist
Pharmacokinetics & Clinical Pharmacology
Drug Metabolism
Array BioPharma, Inc.
3200 Walnut Street
Boulder, CO 80301
burgess.freeman.-at-.arraybiopharma.com
http://www.arraybiopharma.com/
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The following message was posted to: PharmPK
Hi Burgess,
I occasionally put the THU spiked vacutainers at -20 if a subject
fails last-minute screenings. Aqueous stability of THU at -20 is OK
for months (see Parise RA, et al. Rapid Commun Mass Spectrom.
2007;21(13):1991-7.). At room temperature, long term stability may be
a problem. Xiang et al. (JOURNAL OF PHARMACEUTICAL SCIENCES, VOL. 92,
NO. 10, OCTOBER 2003 P.2027) describe THU degradation in aqueous
solution. This is assuming no bacteria are introduced that chew up the
heparin and THU.
Another issue may be the vacuum. I have been able to use vacutainer
tubes even after a week or 2, without apparent loss of vacuum. If you
want to do this for other sites, I would recommend assessing vacuum
after various periods of storage at -20 oC. Another issue again is
(air)shipment, will that affect the vacuum....??
Good luck, Jan
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Vacutainer tubes are BD materials. Unless BD approves the tubes for
the application, you will be on thin-or none existent ice when trying
to put this past the FDA. You will need to validate this
application, re recovery and stability.
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Do you have a validated method for your analyte(s)? Was it performed
in the presence of THU? Anecdotal information will not work! If not,
you will need to re-validate performance of the the analyte method
when samples are collected and stored in the presence of THU at the
concentration of THU you select. Suggest that you do not risk
collection of pateint samples until you know the impact of THU on the
assay. The down side of the risk is that you will need to repeat some
or all of the study. Are you actually going to have the clinical
collectors add this to the vacutainers? Not a good idea- you have
just compromised the integrity of the collection tube and put
uneccesary responsibility upon the clinicians. Suggest you look at
alternatives- such as adding after the lab receives plasma or, if
critical enough, have the THU added by a specialty manufacturer, or
central lab.
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