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I am working on the in-vitro dissolution of a pH -dependent pellet
capsule.
The pellets are coated for drug release in stomach,pH value over 5.5 and
over 7.0 respectively. So I have to change the dissolution pH values at
a
certain time. My question is
1. How to change the pH values at 2hr and 4hr respectively so that the
dissolution pH is 5.5 and 7.0 correspondingly.
2. Compared with testing drug release in simulated gastric solution and
simulated intestinal solution, is there any differnece in testing drug
release in different pH media adjusted by adding buffer solution ?
Thanks for your comments
Xiaolin
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Hi
I would suggest that you make use of a method called the half change
method.
In this method one starts with the simulated gastric juice. At
predetermined
time intervals half of the dissolution medium is replaced by simulated
intestinal fluid. So gradually you will end up with the intestinal
fluid as
dissolution medium. This method exists already for a very long time;
unfortunately generally forgotten !
Good luck
Prof. Dr. R. KINGET
Dorpsstraat 139
B-3060 BERTEM
Belgium
Tel/Fax 32- (0)16 49 01 49
http://www.farm.kuleuven.ac.be/pharbio/vraagbox.htm
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Copyright 1995-2010 David W. A. Bourne (david@boomer.org)