PharmPK Discussion - Endogenous Molecules

• On 18 Apr 2012 at 19:43:09, kanchan soni (kanchansoni.-a-.gmail.com) sent the message
  

  
  Dear All,
  
  Does anybody go through the procedure for extraction of endogenous molecules
  (eg. Niacin, Nicotinamide, Nicotinuric acid etc...) from Human Plasma By
  LC/MS/MS.
  
  Please share your views because interference at the RT is very difficult to
  remove even after many trials of sample clean up procedure.
  
  Thanks
  
  --
  
  Regards
  Kanchan Soni
  Sr. Research Associate-BioAnalytical
  Veeda Clinical Research
  
  

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• On 19 Apr 2012 at 10:01:53, (Noel.Gomes.-at-.accutestindia.com) sent the message
  

  
  Dear Kanchan,
  
  Working on endogenous assays is always tricky. You will almost never get a clean
  blank sample. You will have to perform a baseline correction for the same. Try
  running your selectivity with differnet lots of matrix. Select a few lots with
  least interference and then pool them together. Run a few blank with IS samples
  from the pooled lot. This would give you a cumulative baseline reading. Using
  this pooled plasma then try to establish your calibration curve by using the
  standard addition method. You can use the same apporach for your QC's. In the
  study analysis, you should then use the same approach for calibrants and QC's.
  
  Alternatively you could also try to use a surrogate calibration curve or even
  use Stripped matrix for CC and QC preparation.
  
  Hope this helps.
  
  Warm Regards,
  
  Noel Gomes, PhD
  

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