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The following message was posted to: PharmPK
Dear All,
Do we need to keep the same Blood sample collection time points for
fasting
& fed Bioequivalence studies for a immediate release drug even if
there is
food effect & the time at which Cmax occurs varies by two to three hours
between the fasting & fed state. Your suggestions will be highly
appreciated
Thanks
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The following message was posted to: PharmPK
Dear Dr Vijay,
Blood sampling time points shall be selected to capture the Tmax
accurately, if there is a shift in Tmax under fed condition you have
to select the time points around the tmax as reported under fed
condition.
Regards,
Manojkv
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The following message was posted to: PharmPK
Dear Dr. Vijay
It is certainly not required to have same time points for the fasting
and fed bio-study of same pharmaceutical product. Tmax and T1/2 are the
important parameters to define the time points. If food have some effect
on Tmax of the drug, one can have different time points in fed study.
Regards
Mitesh Gandhi
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Dear Dr. Vijay,
You may change time points for fast and fed study to catch tmax and
cmax effectiely.
Regards
Anuj Saini
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The following message was posted to: PharmPK
Dear Dr.Vijay,
It should be different and it cannot be same for both
fasting and fed studies. It should be according to the
literature available.
Regards,
Dr.Sridhar
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The following message was posted to: PharmPK
Dr. Vijay
It is not required to maintain the same time points
for fasted and fed studies if there is a shift in the
Tmax. It should be noted that the test and reference
formulation Pk parameters are compared in fed Vs fed
and fasted Vs fasted conditions only.
V.Rajesh
CRA-Omnicare Clinical Research Pvt Ltd
INDIA
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Hi Dr. Vijay,
No, it is not necessary to have same timepoints...
you can have different timepoints for fasted and fed-state studies..
plz refer USFDA guidelines on food effect BE studies where it is
clearly mentioned that fast and fed studies can have different
sampling timepoints...
Hope this helps..
Cordially,
Dr. Renu Jain
Research Associate
Clinical Research & Regulatory Affairs
Torrent Research Centre,
Village: Bhat, Dist: Gandhinagar - 382 428
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[A few more replies - db]
Dear Dr. Vijay,
The timepoints should be different. Kindly adjust the timepoints
according to the tmax in fasting and fed state. My advice: also take
inputs from the in-charge of PK analysis.
Regards,
Dr. Gagandeep Singh
Head - Clinical Research
B i o e q you i v a l e n c e C e n t are e
B i o A are c R e s e a are c h S o l you t i o n s
2 n d F l o o r, B h a i l a l A m i n G e n e are a l H o s p i
t a l
V a d o d a are a - G you j a are a t 3 9 0 0 0 3
-
Dear Dr Vijay,
In general, the sampling time points are chosen to capture the true
estimates of Cmax, Tmax, AUCt, percent extrapolation of AUC (0-t)
to infinity and the elimination rate constant (which require minimum
of 3-4 time points from Clast to Cmax), in a BE study. There should
be sufficient sampling time points (at least 3 to 4) around the
expected Tmax to capture the actual Cmax, at least 3-4 time points in
the absorption phase and at least 4-5 time points in the elimination
phase (or more time points depending upon the half-life of drug, to
assure that we cover at least 80% of extrapolated AUCinf as AUCt).
Now if there is a delay in Tmax under fed conditions then certainly
we need to revise the time points for the fed study. The aim should
be to capture the true Cmax and there should be sufficient time
points along the expected range of Tmax. For eg. if the observed (or
reported) mean Tmax under fasting is 2 hr and there is a delay of 2
to 3 hrs under fed conditions. Then our expected Tmax for the fed
study becomes 4 to 5 hrs and accordingly we should take the sampling
time points to get a best estimate of Tmax and consequently Cmax.
Pankaj Mishra
-
Dear Dr. Vijay,
Not at all.
What you need is find the exact time Vs conc. curve by anticipating
the time to maximum concentration.
hirenpharm.-at-.gmail.com
-
Dear Vijay,
The blood sample collection time points are designed on the basis of
Tmax (time at which Cmax occurs) and t1/2. Thus, it is obvious that
when two studies have different study designs (fasting/fed in our
case), then the sampling points will be chosen on the basis of
expected Tmax in the studies (t1/2 shall remain constant).
In nutshell, the sampling points will not be same. in fasting, there
may be more closely spaced sampling points in earlier hours (to
capture early Tmax) and in fed study, they may be decided to capture
late Tmax (assuming that food is delaying Tmax).
I hope this answers your query.
regards
Kshitij
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The following message was posted to: PharmPK
Unfortunately I have seen people still debating indistinctly that the
sampling time points for both Fasting and Fed studies can be similar,
which is absolutely wrong.
For Immediate-release drug products, food can affect Cmax and the
time at which this occurs (Tmax) by delaying gastric emptying and
prolonging intestinal transit time.
The nutrient and caloric contents of the meal, the meal volume, and
the meal temperature can cause physiological changes in the GI tract
in a way that affects drug product transit time, luminal dissolution,
drug permeability, and systemic availability. Hence, Food effects on
BA can have clinically significant consequences.
So, for both fasted and fed treatment periods, timed samples in
biological fluid should be collected from the subjects to permit
characterization of the complete shape of the plasma concentration-
time profile for the parent drug. Consideration should be given to
the possibility that co-administration of a dosage form with food can
alter the time course of plasma-drug concentrations so that fasted
and fed treatments can have different sample collection times inorder
to capture all the necessary PK parameters adequately.
Regards,
Shravan Kumar.Eduru.
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