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dear friends
i am doing felodipine method development, we achived 25pg as LLOQ, but
the problem i m having an cross contamination
(interference peak) at the retention time of analyte as well as
Internal standard i have tried all passible ways i am unable to find
from where the contamination is coming (both SPE and LLE method) but
in diluent there is no interference peak,its only coming in plasma
samples only,can any one suggest me how to reduce and rectify this
problem.
regards
R.Gopinath
R.Gopinath
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Dear Gopinath,
Interference is a veered issue to handle. Sit and look at all sorts of
possibilities. In a recent method development, I faced a similar
problem. Interference was traced to Eppendorf tubes used for
processing samples, and storing plasma. When I used glass vials for
storing plasma and glass test tubes for processing, interference
disappeared. You can consider this approach,if not tried already.
Regards,
Vinayak
Vinayak Nadiger
Manager , Bioanalytical Chemistry
11 Biopolis Way, Helios #08-05
Singapore 138667
E Mail: vnadiger.at.combinatorx.com
Website:www.combinatorx.com
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The following message was posted to: PharmPK
Dear friend
R.Gopinath
Pls clean the source and orfice also and check with the different
plasma lot.
thanks
Dr.Anurag Singh Chauhan
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How are you extracting your plasma samples?
s.o.o
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Gopi
What all solvents are you using? Are you by any chance recycling
anything?
when you inject the neat solution you don't get the interference.
correct? does the neat solution have the drug in it. Did you verify
if your standard is not contaminated? Did you check your pipettes?
it is really not that simple unless you elaborate on the problem.
Thx
Manish Issar, Ph.D
Manager Biopharmaceutics
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