RE: Correcting for salt vs. base
Dear all,
As you say, to obtain the correct pharmacokinetic parameters, the mass of dose
and concentration should be related to the same entity, in this case the base.
This would correspond to using molar units for both dose and concentration.
I believe and hope most people are aware of this, and, the main rule is that
the strength in mg (mass unit) of a medicinal product given on the packages
refers to the base, not the salt, since different salts of the same substance
may be used. (however there are some exceptions for historical reasons).
All the best from Siv
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Siv Jönsson, PhD
Researcher
Dept of Pharmaceutical Biosciences
Faculty of Pharmacy
Uppsala University
Sweden
http://www.farmbio.uu.se/research/researchgroups/pharmacometrics/
Quoted reply history
From: [email protected] [mailto:[email protected]] On
Behalf Of Fisher Dennis
Sent: den 26 mars 2014 13:57
To: [email protected]
Subject: [NMusers] Correcting for salt vs. base
Colleagues
I have been troubled by a minor issue for some time. Consider the following
situation:
Dose is reported in mg salt
Cp is reported in ng/ml base
Since CL is dose / AUC and AUC is merely the integral of Cp vs. time, in
theory, dose should be converted to mg base (or concentration to ng/ml salt).
However, I am not sure if everyone does that.
In fact, an argument against it is that not doing the conversion permits one to
relate the administered dose (which is usually based on salt) to a Cp value
(usually based on base).
I am interested to hear what approach people use.
Dennis
Dennis Fisher MD
P < (The "P Less Than" Company)
Phone: 1-866-PLessThan (1-866-753-7784)
Fax: 1-866-PLessThan (1-866-753-7784)
http://www.plessthan.com/