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dear everybody
can you please tell me in brief with explaining example how to
calculate time points for BA/BE study by considering tmax , c max
i hope anybody can give favourable response to my request
regards
atul
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The following message was posted to: PharmPK
Dear Atul,
The working group pharmacokinetics of the AGAH (Association for Applied
Human Pharmacology) has published the results of thier discussions about
PK items in a text book. Please find an extract from section 10.3 of the
text book 'Parameters for Compartment-free Pharmacokinetics':
....The blood sampling period should be continued for at least
three-times, preferably five-times, the terminal half-life following
tmax. Such a procedure is only meaningful if the bioanalytical
methodology has been correspondingly developed i.e. following
administration of a certain single dose, the mean plasma concentration
of the compound of interest [drug and/or metabolite(s)] at time t 5*t1/2
should be greater than the lower limit of quantification (LOQ, see
Section 3.2).
The time points for blood sampling are usually fixed as follows: the
total number of time points is ideally 15. The first five time points
are selected before tmax (inclusive), the second five time points
between tmax and t1/2 (inclusive) and the last five time points between
t1/2 and five-times t1/2 (inclusive). If the study procedures are
restricted to 12 time points for blood sampling, four instead of five
time points should be selected within each of the aforementioned three
periods. Figure 10.2 gives a plasma concentration versus time profile
of a drug with tmax of one hour and t1/2 of 12 hours. Therefore, the
following time points for blood sampling post administration of a single
dose were selected:
- before tmax (inclusive): 0, 0.25, 0.5, 0.75, 1 hour;
- between tmax and t1/2 (inclusive): 1.5, 2, 4, 8, 12 hours;
- between t1/2 and five-times t1/2 (inclusive): 18, 24, 36, 48,
60 hours.
Best regards,
Willi
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Copyright 1995-2010 David W. A. Bourne (david@boomer.org)