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Dear,
Amlodipine is a racemic mixture of [-]S and [+]R-enantiomeric forms, with the S-amlodipine, also
known as Levamlodipine, having analgesic activity.
Considering the main objective in bioanalysis will be development an achiral method, simple,
sensitive, rapid and reliable mass spectrometry for the quantification of S-amlodipine in human
plasma. I ask you,...can I use Amlodipine (racemic) instead of S-amlodipine (enantiomeric form) as
analitical standard?
Note: The volunteers just will administrate Levamlodipine.
Best regards!
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Dear,
using a racemate for amlodipine for analytical standard would not be acceptable as racemate will
have both R and S isomers present. So prepared Calibrators and quality control samples concentration
will not be accurate( because weighing of standard is a racemate). So concentration of unknown
samples will be inaccurate. Kindly procure only S-amlodipne for analytical standard too.
Regards,
ikhtiyar khan
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Hi Maurico
you can use racemic instead of S-Amlodipine, but you must have percentage of (-)S form present in
the racemic mixture, generally it is provided by the vendor (available on the label), prepare
calibration samples with racemic form of Amlodipine, multiply analyte area of each sample with ratio
of (-)S present in the racemic form, plot the calibration curve, get the equation, now you determine
conc of unknown samples from this equation
Murari
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Hi Mauricio-
By definition, a racemate is 1:1 ratio of each enantiomer. Since your method is not a chiral
method, you should be able to use racemate as reference standard, which will give total amlopidine.
Note that any inactive enantiomer present (e.g. contamination, racemization) will be determined as
part of the total. As long as the method states that it is not chiral and therefore quantifies
total amlopidine, you should be OK. Even if you used the enantiomerically pure material as
reference standard, in an achiral method you would still be determining total.
-Tom
Thomas Tarnowski, Ph.D.
Director, Bioanalalytical Chemistry
Gilead Sciences, Inc
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Yes I think that could be possible but you should be able to accurately estimate how much of S
isomer is present in the racemic mixture.
-Manish
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I concur with Tom, since the method is achiral, either isomer will elute with the same retention
time and have similar signal intensity. Therefore it doesn't matter which one you use, S, R or a
mixture to prepare the standard curve and you don't need to know how much of either is in the
mixture, just the achiral potency.
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