PharmPK Discussion - Low volume blood stabilizer

• On 17 Jun 2013 at 20:21:46, "Pelto, Ryan" (PeltoR.-at-.alxn.com) sent the message
  

  
  Hello,
  I have a discussion topic I would like to post.
  Dear all,
  
  My question is of a practical nature, involving the addition of a stabilizing
  agent to a neonatal blood sample. Ascorbic acid must be rapidly added to
  the
  blood samples to prevent oxidation of our analyte (a pterin derivative)
  and I am
  having trouble finding a practical solution.  Does anyone have experience with
  vendors who will make custom filled collection tubes for microscale-blood
  sampling (~300ul). Any suggestions or experience in this area would be
  appreciated.
  
  Thanks,
  Ryan
  
  Ryan Pelto, Ph.D.
  Scientist II, BioAnalytical Development
  Alexion Pharmaceuticals, Inc.
  352 Knotter Drive, Cheshire, CT 06410
  

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• On 18 Jun 2013 at 01:30:54, "Beumer, Jan H" (beumerjh.at.upmc.edu) sent the message
  

  
  The following message was posted to: PharmPK
  
  From: beumerjh.-a-.upmc.edu
  
  We have good experience pre filling vacutainers with solutions of enzyme
  inhibitors. If you use a tuberculin syringe, the vacuum stays intact.
  
  Jan
  
  --
  The following message was posted to: PharmPK
  
  From: zafar_iqbal.-a-.upesh.edu.pk
  
  Dear Ryan,
  
  I used o-phosphoric acid to prevent oxidation in blood samples.
  
  Dr Zafar
  
  --
  The following message was posted to: PharmPK
  
  From: wxinting1986.-a-.gmail.com
  
  Dear Ryan,
  
  I am not sure if there's any vendors who could provide customized tubes.
  But the
  common in our lab is to add those anti-oxidation agents by ourselves, if
  the
  investigated compound is easily oxidated. I see that the sampling volume
  is
  around 300 ul, so adding 10 ul of ascorbic acid would not make a huge impact on
  the matrix of the blood samples. You could gently stir the sample after
  blood
  collection.
  
  --
  The following message was posted to: PharmPK
  
  From: jasper.dingemanse.-at-.actelion.com
  
  I recommend to take dried blood samples instead, these are much more stable.
  
  Jasper
  
  

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• On 19 Jun 2013 at 12:59:52, "Newman, Edward" (ENewman.at.coh.org) sent the message
  

  
  The following message was posted to: PharmPK
  
  The trick is that you can only put enough solution in the syringe for one tube
  at a time because of the vacuum will suck out whatever volume is in the
  syringe.
   Use the smallest syringe and finest needle available.
  
  Ned
  
  

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• On 20 Jun 2013 at 13:56:06, "Pelto, Ryan" (PeltoR.aaa.alxn.com) sent the message
  

  
  The following message was posted to: PharmPK
  
  Thank you for the ideas. Does anyone have experience with the regulatory
  ramifications of spiking a vacutainer? Even if done with aseptic technique I do
  not believe this can really still be considered sterile anymore. Also are there
  any specific guidelines for controlling performance or stability, depending on
  how far ahead of collection the spike is made. I am thinking of this for
  human
  studies.
  
  Thanks,
  Ryan
  
  

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• On 21 Jun 2013 at 14:22:53, "de Jong, Jan [JRDUS]" (JDejong1.-a-.its.jnj.com) sent the message
  

  
  The following message was posted to: PharmPK
  
  Hi Ryan,
  
  In the mid-nineties I worked on a drug that needed acid stabilization
  and I think I ended up at Greiner who prepared custon-made vacutainers
  with a phosphoric acid solution (few hundred microliter). They used a
  custom-colored stopper. Only problem was I needed to order a couple
  thousand at a time. We did successfully file the drug: I don't think
  there were any regulatory concerns. Of course, these were regular tubes:
  I believe 4 mL.
  
  Best regards,
  Jan de Jong
  
  

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