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Can anybody explain why always drug dosing happens with 240 mL of
water? Is there any rationale behind that?
Thanks in advance
someswara Rao
[To make sure it gets to the stomach? - db]
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The following message was posted to: PharmPK
Dr. Rao,
As far as I know, 240 mL is 8 oz, which is a standard 'cup'. I think
it is a matter of ensuring the drug is delivered completely to the
stomach, and is also convenient for the study participant to
administer.
Glenn
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The following message was posted to: PharmPK
There was a discussion of this last year in the PharmPK archive. This
might
be a good starting point.
http://www.boomer.org/pkin/PK04/PK2004190.html and
Rebecca L. Oberle, Tzyy-Show Chen, Charles Lloyd, Jeffrey Barnett,Chung
Owyang,James Meyer and Gordon Amidon. The Influence of the
InterdigestiveMigrating MyoelectricComplex on the Gastric Emptying of
Liquids. Gastroenterology. 1990;99(5):1275-1282.
Lisa
**************************************
Lisa Tang, Pharm.D
Graduate Student
Pharmaceutical Sciences
(901) 448-6274 (office)
(901) 448-6940 (fax)
ltang.-at-.utmem.edu
[Thanks :-) If the link changes in the future it should be possible to
find it again using the 2004 index or the archive search feature - db]
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The following message was posted to: PharmPK
When I was doing Clinical PK in the early '80s I was told that there
was a study that said this was the optimum amount of water for the
giving a formulation. What drug was used in the study and whether the
study even exists is open to question. This may be some sort of urban
legend.
Dale
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I do not think this is the optimum mode of administration.
To my knowledge, there are two reasons behind the 240 ml volume of
water recommended for oral dosage-form administration in BA/BE studies:
1) The intention was to standardize the volume of liquid in the
GI tract of the subjects, in order to create "similar" conditions for
the dissolution of the active ingredient between subjects and study
periods.
2) As it was already mentioned, the 240 ml correspond to a
regular cup (North-American standard).
It should be noted that not all Regulatory Agencies recommend the same
volume:
EMEA suggests the volume of fluid should be constant (at least
150 ml)
TPD (Canada): "The dose should be taken with water of a
standard volume (e.g., 150 ml) and at a standard temperature"
I hope this helps,
radu
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I think the arguments put forward so far are absolutely correct. The
volume needs to be harmonized either 240ml or 150 ml, however it should
not cross 300 ml because some reports say that at this volume stomach
changes to fed state.
Manoj K. Paruthi
Manager, R&D
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[I updated the PharmPK archive over the weekend using 'new' software
;-) Please let me know if you notice anything 'strange' with the 2005
archive. Thanks - db]
The following message was posted to: PharmPK
Re: 240ml of water for drug dosing.
Dale Sharp wrote that "This may be some sort of urban legend".
IMHO it can be rationalised as follows: Many people find difficulty
swallowing tablets and capsules so, for consistency across the whole
study,
all volunteers are given enough for those subjects to wash the dose down
reasonably comfortably. If they cannot do it with 240 ml they are not
likely to succeed with 350 and more. In any case larger volumes start to
increase variation in the speed of drinking and possibly gastric
emptying...
....although in fact after administering many dozens of test "meals" of
500ml water or glucose solutions I have found quite consistent emptying
provided that subjects are fasting, with half emptying means between 5
and
10 minutes depending upon the study and a CV of <50% being commonly
achieved
in groups of 10 or 12 subjects.
Andrew Sutton
Andrew Sutton, MBBS, MD(London), FFA
Guildford Clinical Pharmacology Ltd.
The Technology Centre, Occam Road
Guildford, Surrey, UK. GU2 7YG
Tel: +44 (0)1483 455375. Direct: 688303
Mobile +44 (0) 7770 820 145 (To 5pm EST)
URL: www.gcpl.co.uk
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The following message was posted to: PharmPK
Dear collegues,
keep in mind that some modifyed release products need water in order to
properly release the drug. To my knowledge the fluid volume in the GIT
(especially in the intestines) is still in vivid discussion and some
experts state that there is not too much water around. A certain
quantity
taken with the tablets could enhance the reproducability of the in vivo
dissolution and thereby the absorption of the drug.
best regards,
Philip
Philip Lienau
Schering AG
Research Pharmacokinetics
Tel.: +49 - 30 - 468 - 18507
Fax: +49 - 30 - 468 - 12238
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The following message was posted to: PharmPK
Dear Dr Sutton,
I read about gastric emptying and this is an old issue
I have some doubts. That is why I decided to write to
you, if you could give me your opinion in this
subject, considering your strong experience.
I usually consider that half emptying mean is 30 min,
would you say so, too?
My concern is related with dissolution profiles.
Sometimes, I have to decide if we carry out or not a
bioequivalence study considering the comparative
dissolution profiles obtained for Test and Reference
(if the pharmaceutical equivalence, was proved).
Sometimes, I have decided that even if f2 is less than
50, but after 30 min, the profiles do not differ more
than 10 %, let's do the study. But this desition was
based on half emptying mean of 30 min.
Would you share this point of view?
Thanks!
Paula
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