Bioanalytical method validation parameters
Hi,
Friends here i try to explain the bioanalytical method validation parameters as per the guideline for easy understanding.
Selectivity
Selectivity
has the ability to differntiate the bioanalytical method and measure the
analyte in the presence of potential Interfering substance in the biological
matrix.Perform
selectivity exercise with 6 indivial sources/lots of biological matrix in
plain, haemolyed and lipemic.
Selectivity
perform for both analyte and internal standard.
Selectivity exercise perform using blank samples
(matrix samples processed without addition of an analyte or IS).The results of Selectivity Should be,no significant
response contribute to interfering components is observed at the retention
time(s) of the analyte or the IS in the blank samples. If Responses detected
and attributable to interfering components should not be more than 20% of the analyte
response at the LLOQ sample and not more than 5% of the IS response in the LLOQ
sample for each matrix.
Specificity
Specificity is the ability of a bioanalytical method
to detect and differentiate the analyte from other substances, including its
related substances (e.g., substances that are structurally similar to the
analyte, metabolites, isomer, impurities, degradation products formed during
sample preparation, or concomitant medications that are expected to be used in
the treatment of patients with the intended indication.
Note:
concomitant medications are like paracetamol, caffine,
cetrizine, diclofenac, Ibuprofen etc.If concomitant
medications drugs are used during study then selectivity for that particular
drugs has to performed.
If concomitant medications are given during study then impact of such substances should be evaluated during method validation or alternatively in the pre-dose study samples.
In the case of LC-MS based methods, to assess the impact of such
substances, the evaluation may include comparing the molecular weight of a
potential interfering related substance with the analyte and chromatographic
separation of the related substance from the analyte. Responses detected and
attributable to interfering components should not be more than 20% of the
analyte response at the LLOQ and not more than 5% of the IS response in the
LLOQ sample.The possibility of back-conversion of a metabolite into the parent
analyte during the successive steps of the analysis (including extraction
procedures or in the MS source) should also be evaluated when relevant (i.e.,
potentially unstable metabolites such as ester analytes to ester/acidic
metabolites, unstable N-oxides or glucuronide metabolites, lactone-ring
structures).It is acknowledged that this evaluation will not be possible in the
early stages of drug development of a new chemical entity when the metabolism
is not yet evaluated.
