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Dear all,
I'm planning to conduct a PK study in patients undergoing peritoneal
dialysis
(CCPD). These patients are under dialysis 7 nights/week, one-day time
exchange
and 4 exchanges at night over 10 hours (average dwell time = 2 hours
with 15
min-20 min fills and drains). In this study, I'm planning to collect
blood
samples but not dialysate samples. In regards to time-point blood
collections,
should I collect during the dwell time (time of exchanges), before the
start of
dialysis or at the end. What would be more reliable in order to assess
at what
extent the drug is cleared by dialysis.
Any help would be appreciated,
Samia Ezzine
Ph.D Student
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Dear Samia,
I would find it useful that you specify the study objectives.
Are you planning to administer the drug i.p. or via another route?
Are you interested in systemic and/or peritoneal exposure to the drug?
In any case, I find it is a pity not to analyse dialysate samples. The
extra
experimental effort is minimal while the exercise is quite informative
about
peritoneal exposure, dialysis clearance, and possibly input kinetics (if
drug is given i.p.).
Dialysis clearance is simply calculated as: peritoneal amount/AUC. It
may be
estimated during each exchange period. A practical consequence is that
you
must take
enough blood samples to estimate an AUC over each exchange period,
including
as a minimum a blood sample at the beginning and at the end of each
period.
Hope this will help.
Henri
Henri Merdjan
Consultant to the Life Science Industries
PK and PK/PD specialist
34, rue des Bergers
75015 Paris
France
hmerdjan.at.wanadoo.fr
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