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I am facing the following issue in a formulation. The Active is
insoluble in acidic pH. I need to compare my product with my innovator
in this media.
Now
1. If a drug is insoluble /very slightly in a media, then how can we
correlate the quantity released from the formulation to the quantity
that is solubilized in the media?
2. Which of the two should be compared to the innovator. Is it the
mg released from the formulation or mg solubilized
3. Which invitro parameter can intimate me about the quantity that
has been absorbed in the blood ?
Any input would be of great use
Best Regards
Vardhini Kirthivas
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Dear Vardhini,
I am confused with your question. You have mixed up the solubility
with that of dissolution. I would like to give some inputs with my view
hope this will help you to understand the matter. First thing is you
need to carry out the BCS solubility of the drug in ph 1 to 8 and find
out the suitable media where the full dose of your drug goes. Once you
get the solubility profiling of the drug then choose the media which is
relevant for the innovator also. Normally you try to select a media
where you can maintain a Sink condition which you can decide by one
simple calculation e.g. when you put a tablet with your max. Dose in
dissolution media the concentration /ml should not be more than 30% of
your BCS solubility it will give your rough idea about maintaining the
sink condition in dissolution bath. To summarize...
1. Make a solubility profiling of drug
2. Decide the dissolution media (use surfactant if necessary with
concentration NMT 2.0%)
3. Carry out innovator analysis
4. Compare your tablet in the same media
5. Now about your last query .......you need to use Wagner Nelson
method to find out % absorbed but again for that purpose you need to
have plasma concentrations .......but I doubt there is any method which
will tell you directly from dissolution profile the % absorbed
I hope I have cleared some of your points
ATUL
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