PharmPK Discussion - Determining wash-out period in BE study

• On 11 Jan 2012 at 21:52:42, Ruby Mosher (mosherru.aaa.ksu.edu) sent the message
  

  
  I'd like to hear what methods others use to determine an appropriate wash-out period for a
  bioequivalence study (crossover) for regulatory data.  When I was a student memorizing
  recommendations such as "10X the terminal half-life," I assumed that meant the MEAN
  terminal half-life.  But it has been suggested that perhaps the number used for the
  terminal half-life in the calculation should be the mean + 2 std deviations to cover 95%
  of the population.  So I'd like to see which value other investigators most commonly use.
  
  Thanks,
  
  Ruby
  

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• On 12 Jan 2012 at 13:41:00, Wichittra Tassaneeyakul (wichittra.tassaneeyakul.-at-.gmail.com) sent the message
  

  
  In general, the compound should be completely eliminate from the
  body after 5 x half-life. So for wash-out period I usually use bout 4-5
  T1/2
  
  Wichittra
  
  

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• On 12 Jan 2012 at 17:42:22, Helmut Schuetz (helmut.schuetz.at.bebac.at) sent the message
  

  
  The following message was posted to: PharmPK
  
  Dear Ruby,
  
  working with means can be tricky, especially if the drug is subjected to
  genetic polymorphism. Mean+/-2SD is not a bad idea (see here:
  http://bebac.at/lectures/BudapestPCWS2.pdf
  - slides 36-37. Try to get as
  much as possible informations on the PK of the drug. It's also a good
  idea to set up simulations in order to get a sampling schedule which
  covers extrapolated AUC < 20% for all (!) subjects.
  
  Guidelines are not helpful (FDA, EMA, WHO: >5x half lives, Canada >10)
  because they don't give a clue what the actually mean by "half live"...
  
  Helmut
  
  --
  Ing. Helmut Schuetz
  BEBAC - Consultancy Services for
  Bioequivalence and Bioavailability Studies
  web     http://bebac.at/
  forum   http://forum.bebac.at/
  
  

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