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The following message was posted to: PharmPK
Dear All,
We have observed a interfering peak at retention time of analyte of CC
std 1 (LLOQ) during subject sample analysis using HPLC. This injection
was continued for longer time. The batch was then stopped for
subsequent injections. It was concluded that there was some
contamination peak which was late eluting. Subsequently the run length
was changed from 15 mins to 18 mins and the batch was reinjected. In
the reinjected run, there was no interfering peak observed at CC std 1
and the peak was acceptable. However, for CC std 2 and CC std 3,
analyte peak was on hump peak . The chromatography for CC std 2 was
not acceptable whereas for CC std 3 was acceptable. Further there was
no interfering peak in subsequent CC, QC and subject samples in
reinjected batch.
We would like to have advise from forum that whether this reinjected
batch is acceptable.
Regards
Dr Ashish Mungantiwar
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The following message was posted to: PharmPK
Dear ashish,
As far as my knowledge it is not acceptable, because as
you had changed the run time, you need to do at least partial validation
running some P&A batches.
Hope I answered your query. Any doubts do revert back.
With Regards,
Veeravalli Vijaya Bhaskar,
Research Associate,
Aurigene Discovery Technologies Limited,
Bioanalytical Division,
Bangalore,
Email: vijay_b.-at-.aurigene.com
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Dear Dr. Ashish,
Regarding the acceptance of reinjected batch from prespective of
regulatory agencies you need to clarify following points--
Is there a SOP for reinjection which directs to stop a batch due to
contamination or processing related error.
If a batch is stopped, one has to document and run some injections to
show that increasing the run time will solve the problem finally.
But I suppose, for that molecule there is a specific run time which
should not also be crossed.
Moreover in such cases of processing related contamination it is
always advisable to process sample on fresh curve as a repeat analysis
because we really don't know how this will affect our subject profile
and therefore not to go for reinjecion unless there is SOP to justify
the cause.
Hope this clears your doubt but you are welcome with any issues.
Regards,
Dipanjan Goswami
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The following message was posted to: PharmPK
Dr. Ashish,
Your problem is directly related to the mobile phase that elutes the
interfereing peak lately. possibly the mobile phase composition and
the column chemistry are improperly judged before the validation.
Try doing this exp: run repeated injections of the same solution for
200 or 300 numbers to see where the interfering peak occurs after the
1st injection. After calculating the cumulative time period make a
note of it.
Try to adjust the MP and the column chemistry and even if the problem
persists, see that you place a blank just after the (cumulative time
divided by run time per injection) injections by which process you can
eliminate anamolous values in your subject sample analysis.
Any info on the physicochemical properties, MP used and column, it can
be better advised.
Regards
Santosh Tata
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