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please through some insight on delayed gastric
emptying and its significane in drug absorption and
also about gastric emptying time and what all it tells
to a pharmacokineticist.
Mr. Neel K. Mohan
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about gastric empting and its significance as reported in
"Veneeta Tandon, Bioavailability and Bioequivalence. In
Pharmacokinetics in Drug Discovery and Development - Ronald D.
Schoenwald Ed.- 2002 CRC PRESS":
Gastric empting - although not true in all cases, increased gastric
empting generally enhances bioavailability of orally administered drugs.
Gastric empting depends on the following factors:
* Volume of liquid intake
* Volume of solid food intake and its fat content
* Viscosity of stomach content
* pH of the stomach
* Intake of other drugs
* Age and weight of the patients
* Physical activity of the patients taking drug
* Emotional state of the patient
* Various disease states
The variability seen in the absorption of orally administered drugs is
mainly due to different rates of gastric emptying, which are affected by
the various factors listed above. Hence, to minimize variability,
ability studies may be conducted under controlled conditions, such as
healthy individuals of controlled weight and age under fasted conditions
or with a controlled diet. The use of healthy subjects minimizes both
and intrasubject variability.
Pharmacokinetic and Tox. Dept.
Inpharzam Ricerche SA - ZAMBON-GROUP
Taverne - Switzerland
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Research demonstrates that carbonate/acid effervescent products
increase the pH (neutralization of acids) of the stomach, which serves
to speed gastric emptying. For substances that are absorbed in the
intestines, this decrease in their transit time through the stomach can
hasten the time to start of absorption (decrease the time to
intestines). In the case of creatine monohydrate, the decreased transit
time results in a smaller amount destroyed by stomach acid and
therefore a larger amount available for absorption in the intestines.
This is how effervescent creatines work. Chelated of creatine, however,
doesn't break down in stomach acid, and therefore doesn't require this
pH disruptive process, which is also incompatible with proteins since
they need an acid environment for digestion.
However, in contrast Kosoglou et al., 1995 concluded that in the
presence of food, gastric emptying time is considerably increased
causing a delay in drug absorption and a slight increase in the
bioavailability of 5-ISMN from this controlled-release tablet
formulation, however this effect is not clinically relevant.
Thus for some drugs a delay in gastric transit time actually may lead
to increase in bioavailability of drug.
Thanks and regards
[SORRY, SORRY, SORRY - I don't really know what happened yesterday. I
believe I have stopped the 'bad' message from yesterday and I send this
new message out with some trepidation. I'll be watching closely. I
don't know if everyone got 180 copies of the message but I know quite a
few did (as I did in digest mode). Thanks for letting me know.
Unfortunately I was out of town when I sent the first message and
during the multiple messages problem, until about 11:30 last night.
I've had about 3-4 similar problems in the past year or so but on those
occasions it seemed that only one poor person received the multiple
messages. I had a couple of those problems in the last week and was
able to stop them. They seemed to occur when the server crashes which
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restart the server on Saturday and watched for problem messages but
nothing seemed wrong at that point. I should say these problems don't
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appeared for submission to PharmPK. I was out of town and because of
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through my listserv software (which seems to be OK) to my mail server
where I think the problem existed. I'm about to try it again ... last
week I have been setting up a new machine with different mail software
(postfix replacing sendmail). I plan on starting that up this afternoon
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