Back to the Top
Dear all,
I have intrasubject variability established in two-way crossover study
where two formulations of suspension were tested.
Now I need to prepare a BE study of the same compound but in tablet
form and my question is can, intrasubject variability obtained from
suspension study, be used in determination of subject sample size in
tablet study.
All your suggestions will be welcomed!
Regards,
Lidija
Back to the Top
The following message was posted to: PharmPK
MINTAB,SAS, electronic handbook of probality will aloow you to input the
target difference, probability limits and known sample variance and
give you
an output of required sample size.
--
Ed O'Connor, Ph.D.
Laboratory Director
Matrix BioAnalytical Laboratories
25 Science Park at Yale
New Haven, CT 06511
Web: www.matrixbioanalytical.com
Email: eoconnor.-at-.matrixbioanalytical.com
Back to the Top
The following message was posted to: PharmPK
Ideally, you want to use the intrasubject variability from the same
formulation, as the variability of the drug may be formulation
dependent. However, in a vacuum, if you have nothing else to look at,
it's better than nothing.. Be straightforward about it in your
justification of sample size.
-Dave
Back to the Top
[New computer, re-indexing my mail client found this message (and
possibly a few more) - db]
The following message was posted to: PharmPK
Dear Dave,
I was thinking something the same and this was my rational, better
something than nothing!!
When we are talking about BE crossover studies this intrasubject
variability is really residual unindentified variability and as we are
trying to control everything except this biological difference in one
person we are assuming that this is the majority of residual
unidentified variability.
Fixed factors in this kind of studies are period, sequence, treatment
and subject nested in sequence, therefore I was thinking that treatment
was already described with some variability and isn't part of this
unidentified variability.
Do you agree or have some other opinion?
I was comparing some our in house studies and I have to say that ISCV
for tablets and suspensions wasn't the same but it also wasn't so
different.
Did anyone have different experience regarding this?
Lidija
Back to the Top
Yes Lidija,
In the mention situation it could be okay to consider the variability
observed during suspension study. When compared to tablet formulation,
suspension can be argued to be a best case because formulation influence
on variability due to the molecule would be nominal.
What do you say??
Regards
Manoj K. Paruthi, Ph.D.
Sr. Manager, R&D
Hikma Pharmaceuticals Plc.
Want to post a follow-up message on this topic?
If this link does not work with your browser send a follow-up message to PharmPK@boomer.org with "Intra-subject variability" as the subject | Support PharmPK by using the |
Copyright 1995-2011 David W. A. Bourne (david@boomer.org)