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The following message was posted to: PharmPK
Dear All,
We at our lab have faced a peculiar problem related to unacceptable
chromatography. In a batch two subjects along with four sets of QC
samples were analyzed using HPLC. After analysis (oververnight run)
it was observed that
1. Chromatography of Subject I period I along with QC samples were
acceptable
2. Chromatography of Subject I period II and Subject 2 of period I
and Period II along with QC samples were unacceptable since it was
showing tailing of IS above acceptance limit (above 1.5) However, the
IS area and back calculated QC concentrations were well within
acceptance limit.
On this situation we have two questions
1) Whether to accept batch on the basis of back calculated QC
concentrations OR to Reject batch on basis of unacceptable
chromatography of QC samples even though back calculated concn. of QC
samples are with in range
2) Whether to accept the subject I period I samples whose
chromatography is proper (Chromatographically QC samples placed with
these P I samples are also proper) and repeat only those samples
whose chromatography is not acceptable?
We look forward for an opinion on the above query
Dr Ashish Mungantiwar
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The following message was posted to: PharmPK
Generally you should have aceptance criteria for retention time,
resolution and peak shape, before you back calculate. If the peaks do
not meet these criteria, the sample, whether QC or patient or standard
fails.
Ed O'Connor, PhD
Technical Director, Immunoanalytical
Tandem Laboratories
115 Silvia Street
West Trenton, New Jersey
609-228-0243
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Dear Dr. Ashish,
If ur SOP says unacceptable chromatography if tailing of IS is above
1.5 then the results has to be rejected eventhough all the QCs are
passing. Also QCs rejected due to poor chromatography cannot be
accounted in batch acceptance criteria thereby producing Unacceptable
batch and hence entire batch has to be reinjected (If within
Autoinjector stability duration) or repeat analysed.
Dr. Mandar Mote
Head Bio-analytical
CRO
Cadila Pharmaceuticals Ltd.
Ahmedabad
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Dr.Ashish,
The Problem is quite regular in BA/BE studies. If you are working
with a moderabtely basic compounds there is a problem of Silanol
interactions that cause tailing to be enhanced with time. although
the columns we feel are bonded with C18/C8 only 50% are bonded and
the rest remain free accounting for tailing. this is one aspect of
reasoning.
One good thing is to follow the criteria of method SOP. Accept the
Sub 1 period 1 samples as passed because they passed and Sub 1 Per 1
and Sub 2 samples as failed. they may be reanalysed after running a
PA batch.
Inviting opinion from experts.
Santosh Tata
Bioanalytical Division, BEC,
Apotex Inc, Bangalore
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Dear Dr Ashish
I would say you can confidently accept the Subject 1 and period I
samples for which you have placed a set of QC's. But, it would have
been more clear if you exactly mention regarding tailing status of
the IS. Obviously, a greater tailing will be unacceptable.
As you have mentioned the QC's are passing, you can go for acceptance
of other samples also, provided your SOP and internal guidelines
permit the same.... I personally feel a reanalysis of these samples
will be preferred if possible to say your results with confidence.
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Dear Dr. Ashish,
If your SOP says unacceptable chromatography if tailing of IS is
above 1.5 then the results has to be rejected even though all the QCs
are passing. Also QCs rejected due to poor chromatography cannot be
accounted in batch acceptance criteria thereby producing Unacceptable
batch and hence entire batch has to be reinjected (If within
Autoinjector stability duration) or repeat analysed.
Dr. Mandar Mote
Head Bio-analytical
CRO
Cadila Pharmaceuticals Ltd.
Ahmedabad
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Dear all,
Peak tailing with analyte/IS above limits is unacceptable as it
always leads to improper quantification of the samples. i suggest
follow the SOP n reanalyse the samples with fresh set of QC's. it is
suggested that you alternatively inject period 1 and period 2 for
better uniformity in chromatography in one particular subject.
regards
Abhijith Rao
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