PharmPK Discussion - PK preclinical

• On 7 Oct 1996 at 11:18:31, David Bourne (david.-a-.pharm.cpb.uokhsc.edu) sent the message
  

  
  [Originally from "Joan Garrell" 
  
  I have just arrived to PK field, working in preclinical studies.  I am
  trying to manage data and statistics when comparing bioavailability data
  obtained from independent animals (one point, one animal).  I have only
  found a method of calculating and comparing AUC obtained in this way
  from Shoenwald et al. I'd apreciate any help in how to deal with
  statistics in bioequivalence studies when a curve is obtained from
  different animals ending with a curve made of medium values but not a
  'medium curve'
  Thanks in advance
  Carmen
  
  David Bourne, Ph.D., OU HSC College of Pharmacy, Oklahoma City, OK 73117
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• On 7 Oct 1996 at 18:01:55, Bob Phair (rphair.-a-.ix.netcom.com) sent the message
  

  
  Re: calculation of bioavailability one point per animal...
  
  Carmen-
  
  Was each animal given the same dose and was that dose expressed per kg body
  weight?
  Were data collected after both intravenous and oral doses or did you use
  some relative
  standard?
  
  What are the units of measurement of your individual data samples? Do you
  have body
  weights or plasma volumes for the individual animals?
  
  Unless all the animals are the same or nearly the same size, it may be
  useful to
  normalize the data set before calculating the AUC. If the dose was given
  per kg, this
  normalization may already be built into your data set.
  
  You can assign statistical weight to the data based on your knowledge of the
  measurement error. Then you can fit the data to a sum of exponentials, or to a
  compartmental model, or use a "noncompartmental" approach as described by
  (for example)
  Gibaldi, M., Biopharmaceutics and Clinical Pharmacokinetics, 4th ed., Lea
  and Feibiger,
  1991.
  
  As with all AUC measurements, you will have to choose some estimate of the
  slowest
  exponential to extrapolate to t= infinity. For this reason, it is always
  desirable to
  have data as far out in time as possible.
  
  Now, when you do your least squares fit you will get point estimates for
  your AUCs and
  you will get coefficients of variation based on your estimate of
  measurement error. For
  this part of the work, my favorite software is SAAM II, but there are many
  other
  capable packages.
  
  Good luck and post again if this doesn't help.
  
  Regards,
  Bob
  --
  Robert D Phair PhD: rphair.-a-.ix.netcom.com
  BioInformatics Services: http://www.webcom.com/rphair
  Partnering and Outsourcing for Computational Biology
  
  

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• On 8 Oct 1996 at 12:11:09, "Vladimir Piotrovskij" (VPIOTROV.-at-.JANBELC1.SSW.JNJ.COM) sent the message
  

  
       Recent article by Ette et al. (J. Pharmacokinet. Biopharm. 1995, 23:
       551) may help.
  
       --
       --------
       Vladimir Piotrovskij, Ph.D.           Fax: +32-14-603768
       Janssen Research Foundation           Email: vpiotrov.aaa.janbe.jnj.com
       Clinical Pharmacokinetics
       B-2340 Beerse
       Belgium
  
  from: "Vladimir Piotrovskij" 
  

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