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Dear All,
I am doing bio analysis of clopidogrel in my laboratory using LC-MS/MS system.I
would like to know few things before starting the plasma extraction of the
compound.
I have read some article suggesting back conversion of clopidogrel metabolite to
clopidogrel if samples are processed in the presence of acid.I would like to
know what could be the possible extraction strategy for the compound without any
back-conversion.
Also there is some confusion regarding back conversion of Acyl glucuronide back
to clopi carboxylic acid or to clopidogrel.
One more thing i would like to know is there any significant effect of lipemic
plasma samples on the extraction of the compound,if there is any, then what
could be the strategy to avoid the same.
Expecting valuable insights..
Dr Jacob
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Hi Jacob
I remember the issue of inter conversion between the prodrug and its active
metabolite. However, I vaguely remember that problems of inter conversion
arose when methanol was used in the sample preparation and clean up. The
substitution of methanol with acetonitrile was helpful to resolve this
problem. Not sure how that was happening but somehow methanol could have
been partly responsible for this issue helping to re-methylate the
carboxylic function in the active metabolite. I am not a chemist but may be
someone else may throw some light on this.
Here is the link to a poster presentation that is available at this URL and
may be helpful in some way.
http://glsciences.com/products/inertsil_hplc_columns/Titansphere/ASMS2006/A061099.pdf
Manish
Manish Issar, Ph.D
Assistant Professor of Pharmacology
Western University of Health Sciences
College of Osteopathic Medicine of the Pacific
Pomona, CA 91766
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Dear Jacob
If you are aiming on the active metabolite concentration, the following article
serve your purpose. The metabolite must be derivatised and extraction method
involves SPE.
Journal of Pharmaceutical and Biomedical Analysis 48 (2008) 1219-1224
Regards
Vijaykumar.S
Senior Research Associate,
Dr Reddy's Institute Of Life Sciences,
University of Hyderabad Campus,
Gachibowli, Hyderabad 500046
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The following message was posted to: PharmPK
The back conversion to clopidogrel and its carboxylate metabolite is from the
metabolite clopidogrel acyl glucuronide when methanol is present.
http://www.springerlink.com/content/l23313832j483146/fulltext.pdf
This should not affect the quantification of clopidogrel active metabolite if
plasma samples are derivatized by 3'-methoxyphnacyl bromide immediately after
collection. I think it is not clinically relevant.
Haojie Zhu
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