PharmPK Discussion - Plasma recovery

• On 23 Mar 2012 at 03:49:19, (mohammadyunusm.at.orchidpharma.com) sent the message
  

  
  Hi,
  Does the % recovery of a drug in plasma changes with the column used? I feel it
  should not as recovery is related to the extraction procedure and no to column.
  Drug is highly polar in nature. Pl let me know your thoughts on this.
  Regards
  Yunus
  
  

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• On 23 Mar 2012 at 21:59:34, vijaya bhargava (vijayabhargava.k.at.gmail.com) sent the message
  

  
  The following message was posted to: PharmPK
  
  yes,
  the extraction efficiency determines your % recovery in studies like
  plasma protein binding etc; if all other parameters like tailing, or
  asymmetry and P&A batch are in-line with bioanalytical rules. But an
  recent study on the role of recoveries in plasma protein binding
  studies with apparatus like equilibrium dialysis indicates that the
  recovery has a small role to play in determining the test
  procedure..But this has to be worked in detail yet.
  
  the reference is
  Impact of recovery on fraction unbound using equilibrium dialysis
  (journal of pharmaceutical sciences).
  
  vijayabhargava
  
  

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• On 26 Mar 2012 at 09:29:47, (JigneshKotecha.-at-.torrentpharma.com) sent the message
  

  
  Yunus,
  
  It may change if it is evaluated against neat solution and Mass is the detector.
  With different columns, there could be a change in elution pattern of matrix
  ions as well, which may interfere in ionization of drug. But if it is evaluated
  against extracted matrix spiked with respective conc. then it should not affect
  the % recovery.
  
  Please confirm my observations.
  
  Thanks and regards,
  
  Jignesh
  

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• On 26 Mar 2012 at 14:05:09, "Edward O'Connor" (efoconnor.at.gmail.com) sent the message
  

  
  The following message was posted to: PharmPK
  
  Run extracted vs non extracted (extraction buffer or loading
  solution).   One is never sure what the extracted matrix contains.  To
  limit uncertainty, compare extracted sample response vs target
  concentration in extraction buffer and/or loading solution for column.
  
  

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• On 28 Mar 2012 at 03:31:35, (mohammadyunusm.-a-.orchidpharma.com) sent the message
  

  
  The following message was posted to: PharmPK
  
  Jignesh/Edward/Vijay,
  Thanks for your response. Probably what Jignesh said in his response ("But if it
  is evaluated against extracted matrix spiked with respective conc. then it
  should not affect the % recovery") sounds logical.
  Let me reframe my question again for better clarity. When an extracted matrix
  (spiked with analyte) is injected into LCMSMS using one column (e.g. Phenomenex)
  and similar (or same) matrix later reinjected using another column (e.g. YMC
  PACK, both columns are similar in nature), and when respective % recovery
  calculated w.r.t neat solution, does the % plasma recovery remains same?
  
  Thanks for your inputs.
  Regards
  Yunus
  

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• On 28 Mar 2012 at 22:41:37, vijaya bhargava (vijayabhargava.k.aaa.gmail.com) sent the message
  

  
  The following message was posted to: PharmPK
  
  essentially it should be the same ( if mobile phase and solvent of
  extraction are kept constant), because extraction technique is
  something related to the organic solvent used and the capacity of the
  solvent to extraction the whole amount of drug bound to the matrix.
  So, it should be the same..according to me and my experience in
  calculation of percent recoveries.
  vijayabhargava
  
  

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• On 29 Mar 2012 at 09:36:36, (JigneshKotecha.-at-.torrentpharma.com) sent the message
  

  
  Yunus,
  
  "But if it is evaluated against extracted matrix spiked with respective conc.
  then it should not affect the % recovery", here first extract the blank matrix,
  reconstitute/elute with specified solvent and then spike with respective conc.
  Treat this as reference for %recovery evaluation using different column.
  Comparison of extracted samples with neat solution using different column may
  result in different recovery.
  
  Jignesh
  
  

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• On 29 Mar 2012 at 09:51:16, (Deepak.Jain.-a-.sunpharma.com) sent the message
  

  
  Dear Yunus,
  
  I would like to add, that recovery variation depends on lot many factors when to
  be estimated on two different make of columns
  Purity of silica (metal ions, etc.)
  Carbon loading (Impacting the retention of analyte and matrix)
  pH range (may be same, but may effect the Si-OH differently depending on the
  purity of silica)
  Column conditioning (sufficient time)
  Column stabilization with pure neat and or extracted samples (sufficient number
  of samples)
  Different retention time on both column
  Retention and elution of matrix on column
  Finally the suitability of optimized source parameters, leading to stable
  ionization &
  Source stabilization
  Evaluating all these factors shall give you sound idea about your method of
  extraction and method of analysis.
  Hence the response to your query is that, the recovery may or may not remain
  same when trying to estimate it on two same but different make of column.
  
  Thanks
  
  Best Regards
  
  Deepak Jain
  

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• On 29 Mar 2012 at 14:24:03, (vinodpatil.at.lupinpharma.com) sent the message
  

  
  The following message was posted to: PharmPK
  Dear Yunus,
  
  If you change the column and re-evaluated the recovery of same spiked samples
  against analyte in solution, it may results in change in recovery. If the peak
  is eluting on one column in presence of matrix and on another colum , it is
  seperating from matrix componant.Then this results in diffrential matrix effect
  on same sample on two different columns and eventually it will come out
  difference in recovery. I hope, it may help.
  
  Thanks & Best Regards
  
  Vinod Patil
  

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