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Respected All,
Please share your valuable suggestions related to this case study.
We have developed a method for one analyte & its metabolite, (drug has labelled
ISTD & metabolite has analogue ISTD), Validated it with all related experiments,
all were within acceptable criteria.
Than we have completed Study sample analysis for approx 120 subjects.
Now we went for Incurred Sample Analysis (ISR), In one batch of ISR we observed
the batch was found out of acceptance criteria for metabolite because of
regression was out of acceptance criteria (less than 0.99), more than 99%
samples were found within acceptance criteria for drug when compared with
initial analysis.
After that we repeat the batch for metabolite (ISR Repeat), results shows more
than 60% samples were found out of acceptance criteria (more than 20% Bias), on
the other hand all samples all samples were found within acceptance criteria for
Drug.
Investigation as follows:
1. No significant interference were observed in STD BL , carryover STD BL
samples, which mean no contamination while processing.
2. Peak shape, retention time were found ok.
3. consistence ISTD response was observed for both drug & metabolite.
4. Then we reinjected 10 samples under investigation batch along with both CC
sets & 2 sets of QC samples, results were compared with initial samples and we
found 7 out of 10 samples were within acceptance criteria for metabolite.
5. when investigation samples were compared with ISR samples (which was failed
due to regression), all samples were within acceptance criteria.
6. when ISR samples were compared with investigation batch we found all samples
were more than 20% bias (not accepted).
Based on above investigation we concluded that there might be some system
related problem might be happened & after about 2 hour flushing of system we
decided to re-inject whole batch after performing system suitability experiment
& system performance experiment.
The whole reinjected batch when compared with initial analysis we found that
more than 80% samples were within acceptance criteria.
Now my question is can we accept the reinjected batch for ISR???
is it acceptable by Regulatory Authority???
or we have to select more samples for ISR
Thanks in advance.
--
Regards
Kanchan Soni
Sr. Research Associate-BioAnalytical
Veeda Clinical Research
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> Now we went for Incurred Sample Analysis (ISR), In one batch of ISR we observed
> the batch was found out of acceptance criteria for metabolite because of
> regression was out of acceptance criteria (less than 0.99), more than 99%
> samples were found within acceptance criteria for drug when compared with
> initial analysis.
If the regression failed how did you get results for the ISR?
> 1. No significant interference were observed in STD BL , carryover STD BL
> samples, which mean no contamination while processing.
> 2. Peak shape, retention time were found ok.
> 3. consistence ISTD response was observed for both drug & metabolite.
> 4. Then we reinjected 10 samples under investigation batch along with both CC
> sets & 2 sets of QC samples, results were compared with initial samples and we
> found 7 out of 10 samples were within acceptance criteria for metabolite.
> 5. when investigation samples were compared with ISR samples (which was failed
> due to regression), all samples were within acceptance criteria.
> 6. when ISR samples were compared with investigation batch we found all samples
> were more than 20% bias (not accepted).
What is the % Bias normally? How much over 20%
>
> Based on above investigation we concluded that there might be some system
> related problem might be happened & after about 2 hour flushing of system we
> decided to re-inject whole batch after performing system suitability experiment
> & system performance experiment.
Did you run suitability before each run?
>
> The whole reinjected batch when compared with initial analysis we found that
> more than 80% samples were within acceptance criteria.
>
> Now my question is can we accept the reinjected batch for ISR???
Outline the logic would you accept the perfromance. If you get one failure and one
success you will need another to break the tie.
> is it acceptable by Regulatory Authority???
Not without reason for rejecting the failed run and without a tie breaker.
> or we have to select more samples for ISR
Did suitability pass each run? What is used to reject the failed runs (other than the
one that failed suitability)?
--
Edward F. O'Connor
78 Marbern Drive
Suffield, Ct 06078-1533
T: 860-668-6201
C:860-324-6780
efoconnor.aaa.cox.net
efoconnor.-at-.gmail.com
www.aegisbioconsult.com
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Dear Kanchan Soni,
Based on your results of investigation and ISR results, it can be concluded that
the batch can be accepted after reinjection.
However, since it is a pivotal study and to avoid any queries by regulatory
agencies, it is better to select more number of samples
(at least 5% of total unknown) and complete the ISR as per requirement.
Thanks and Regards
Santosh Kumar Manthri
Research scientist
Bioanalytical Research Department,
Synapse Labs Pvt. Ltd,
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The following message was posted to: PharmPK
It may be that the cause of the deviation is more closely associated with the
sample than the system, Kanchan.
* When are the internal standards added during sample prep ? Are there any
processing steps other than thawing prior to their addition ? There have been a
few drugs - for example, some steroid hormones - for which result differed a lot
based on the aliquot taken from the larger serum or plasma sample - indicating
non-heterogeneity, and in such cases one would expect the ISTD responses to be
fine while differences with the primary analyte or metabolite from the in vivo
samples would differ.
* Are the responses that caused the metabolite regression to fail, and the
samples to compare within 20% or acceptance limits associated with a particular
part of the dynamic range of the method ? For example, when 7 of the 10 samples
agree between repeat and original analysis, are the 3 of 10 all roughly the same
concentration ?
* An 80% agreement rate for sample results between the original analysis and
the complete reinjection analysis is not particularly encouraging, and it would
cause me to hesitate to submit these data to a regulatory agency.
As Ed O'Connor has pointed out, it seems more lab investigation and work is
needed.
with regards,
--dean
Dean W. Knuth
President & CEO
Jasper Clinical Research & Development, Inc.
526 Jasper Street
Kalamazoo MI 49007
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Dear madan
You have to select another samples (other than already selected ) as incurred
samples and have to perform isr.
From
Kintan patel
Sun pharma
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Dear Soni,
The ISR batch was reinjected under investigation which i feel should not be considrerd for
reporting of results. Also you are not able to identify the exact cause. It will be better
if you can assign some cause by further invsetigation. or else you can repeat the batch to
confirm the reproducibility of the results and report the results from the repeated batch.
It will be better to close this issue now proactively.
Dr. Mandar Mote
Dy. General Manager Bio-analytical
Bio-equivalence Division
Macleods Pharmaceuticals Ltd.
Mumbai
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Dear Mandar Sir,
A thorough investigation of change in results for samples was done and it leaded to the
review based on the change in slope for Cs obtained during ISR, ISR-investigation and
Reinjected batch and it was found that there was considerable change in % difference
between slopes for the samples of ISR compared to SR-investigation and Reinjected
batch.
Batch ID Slope % Difference
ISR 0.0117 NA
ISR-investigation 0.0156 33.3
Reinjected batch 0.0171 46.2
The outsized amount of difference between the slopes of ISR , ISR-investigation and
Reinjected batch shows that the change in % difference for the concentrations when intra
comparison of values made could have been due to change in slope, where although in ISR
results remained acceptable in terms of Cs and Qcs but it did not behaved as a best fit
for Subject samples and resulted in samples showing % bias of more than +/- 20% for selected
samples. Hence based on this it can be held that the initial results of ISR were not
reliable and which could have been due to below reasons,
v 1. Improper stabilization of chromatographic system.
v 2. Exhaustive behavior of the column,
v 3. Internal standard being an analogue behaved awkward to analysis.
Due to less volume it is not possible to reprocess the same sample,
Regards
kanchan
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Dear Kanchan Mam,
As per my view please find out the %CV for all batches run during study and validation,
may you find some idea of behaviour for curve and if in the same condition any of the
batch you have accepted than you are going in the wrong direction for the investigation.
Please don't take me on wrong way but this are my view...,
With best regards,
Dipak S Haravani,
Sun Pharmaceutical Industries Ltd.,
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Re-injection may not be acceptable by regulators without any identified
analytical root cause.
Kumar
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