PharmPK Discussion - Free drug concentration in tissue

• On 13 Mar 2014 at 10:21:51, Gautam Mishra (gautam.mishra.-at-.daburresearch.in) sent the message
  

  
  Dear all,
  
  Can anyone suggest me how to determine the free drug concentration from tissue.
  
  Thanks
  
  Gautam
  
  [Good 'little' question ;-) In vitro, simulation? - db]
  
  

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• On 13 Mar 2014 at 10:28:10, Paul Hutson (prhutson.-a-.pharmacy.wisc.edu)" sent the message
  

  
  Microdialysis, I would think.
  Paul
  
  --
  Paul R. Hutson, Pharm.D.
  Professor
  Senior Associate Dean for Academic Affairs
  UW School of Pharmacy
  
  [Yes, forgotten about that option - db]
  

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• On 13 Mar 2014 at 11:29:40, Benjamín Santos Lobo (bsantos.at.spheriumbiomed.com) sent the message
  

  
  Red systems. As protein binding working with homogenate tissue.
  
  

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• On 13 Mar 2014 at 14:24:31, David Bourne (david.aaa.BOOMER.ORG) sent the message
  

  
  Hello Gautam,
  
  Besides dialysis there are also tailored assay systems for brain tissue binding, microsomal binding
  and liver binding that are easier to implement and less costly. Which tissues are you interested in?
  
  Cheers,
  Hinnerk
  
  Hinnerk Boriss 
  --
  Micro dialysis is one approach if the drug is not too hydrophobic. Also it will determine drug in
  the interstitial fluid and may not account for levels within cells or cell membranes.
  -Tom Tarnowski
  
  Thomas Tarnowski 
  
  

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• On 14 Mar 2014 at 10:50:22, David Bourne (david.at.BOOMER.ORG) sent the message
  

  
  Dear all,
  Be careful the RED system has a very important non-specific binding
  you can use the equilibrium dialysis, which is the "gold method".
  
  Françoise
  
  Françoise BREE
  Project Management Officer Bio Services
  
  XENOBLIS
  Parc d'Affaires de la Bretèche
  Bâtiment B1
  35760
  Saint Grégoire
  France
  
  francoise bree 
  --
  I would agree with Benjamin regarding the red system and with Tom's caveat re interstitial fluid.  I
  would go the route of perfusion to remove capillary content, then gentle lysis with water followed
  by red system separation of bound from free.
  
  Edward O'Connor 
  --
  Hello Gautam
  The most applicable method for determination of free drug from the tissues is mass assisted laser
  desorption ionization mass spectrometry (MALDI), and there are a lot of articles have been published
  using the same technique. So, for more information see Analytical chemistry and Journal of proteome
  research  both in ACS
  
  Sincerely yours
  
  DR.ELTAYEB E.M.EID, Ph.D.
  (Drug Development and Clinical Proteomics )
  Assistant Professor
  Department of Pharmaceutics
  Uniazah College of Pharmacy, Qassim University
  Qassim, Saudi Arabia
  
  ELTAYEB EID 
  
  

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• On 14 Mar 2014 at 14:29:15, Dr. Prasad Tata (drprasadtata.-a-.yahoo.com) sent the message
  

  
  Dear All:
  
  For all the nice aspects touched upon, my suggestion is to consider practical side in measuring free
  drug concentrations.  If the drug demonstrates same protein binidng measuring plain drug
  concentrations in plasma or tissue and correct for protein binding. This would make more
  non-clinical and clinical relevance
  
  Prasad NV Tata, Ph.D., FCP
  

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• On 18 Mar 2014 at 07:11:04, Stanley Cotler (msgcot2.aaa.optimum.net) sent the message
  

  
  If you need an estimate, please see Pharmacokinetics of Diazepam and
  Nordiazepam in the Cat, J Pharm Sci Vol73, No 3 March 1984, pp348-351.
   Vt=TBW plasma vol., Amt free in blood=Free in plasma/Blood to Plasma
  ratio.  Orginal l reference was JE Gillette, Ann NY Acad Sci, 179,43,
  (1971)
  Ft=Vt-Fb/Vdbeta-Vb
        Stanley Cotler
  
  

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Copyright 1995-2014 David W. A. Bourne (david@boomer.org)