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We have executed a single oral dose PK study with urine sampling in the first 24 hours after dose
included, collected in spontaneous miction samples, all males. The minimal total water load in that
24 hr period was 2.45 L, according to protocol. To our surprise, a few subjects produced way less
volume of urine, e.g. around 1 L or even less, with no obvious errors in sampling and record taking
(clinic setting). Is there any guidance or rule of thumb to set a lower level of urine volume which
can be expected at the load of 2.45 L to more objectively reject the data of subjects with the
unexplainable low volumes.
Guus Duchateau Pharm D
Science Leader ADME group
Unilever R&D Vlaardingen BV
Olivier van Noortlaan 120, 3133 AT Vlaardingen
the Netherlands
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Hi:
My suggestion is not to throw any subject on the basis of urine volume alone. The daily urine
output varies widely between 800-2000 mL ( ref:
http://www.nlm.nih.gov/medlineplus/ency/article/003425.htm ) multiple factors such as BMI, hydration
status, room temperature loss of water due to other routes (sweat etc.) also contribute.
Hope this helps,
Prasad NV Tata, Ph.D., FCP
5620 Clarks Fork Drive
Raleigh, NC 27616
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While I agree that a low volume could be a chance finding, urine collection is notoriously
error-prone if not supervised very strictly even in a clinical setting (i.e., if not locking
washrooms and for males having access to sinks at night). If in doubt, it might be helpful to
measure creatinine clearance based on the samples obtained and to compare the respective results to
estimates of GFR based on plasma creatinine concentrations. Gross deviations could be used to sort
out major collection errors.
Uwe Fuhr
Clinical Pharmacology Unit
Hospital of the University of Cologne, Germany
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