Purpose
A validated analytical method ensures that it provides
consistent, reliable and accurate data thereby confirming its suitability for
its intended purpose. So each method of analysis helps analyst to ensure
quality products are released for market.
To describes the procedure for Analytical Method
Validation.
Procedure:
Definition: A validated analytical method
ensures that it provides consistent, reliable and accurate data thereby
confirming its suitability for its intended purpose. So each method of analysis
helps analyst to ensure quality products are released for market.
Pre-requisite:
Ensure that the method validation activity is carried
out only on calibrated
instruments and by a qualified analyst, carrying valid
qualification certificate for the respective instrument.
All the measuring glassware used in AMV must be under
valid calibration limit complying to class ‘A’ type.
Analytical method validation, for tests like Assay,
Impurities/ related substances should be performed individually.
In case of Assay or impurities profile, system
suitability parameter is an essential part to start the validation activity.
Any analytical method shall be revised through change
control procedure only and shall be duly approved by Quality Assurance and
R&D head.
Whenever there is a need to change critical test
parameters, the method is re-validated with the revised parameters &
conditions.
Parameters
S.No.
|
Method Validation Parameter
|
1.
|
Specificity/ selectivity
|
2.
|
Precision
Repeatability (system precision)
Intermediate precision
|
3.
|
Accuracy/ %recovery
|
4.
|
Linearity
|
5.
|
Range
|
6.
|
Limit of detection
|
7.
|
Limit of quantitation
|
8.
|
Ruggedness
|
9.
|
Robustness
|
10.
|
Solution stability
|
11.
|
Revalidation of analytical method
|
Specificity/Selectivity:
Specificity is the ability to assess unequivocally the
analyte, in the presence of components that may be expected to be present, such
as impurities, degradation products and matrix component.
Specificity/Selectivity parameter establishes that the method can measure the
analyte response in the presence of all potential sample components with
accuracy and precision thus establishing selectivity for the compound.
Precision:
The closeness of agreement (degree of scatter) between
a series of measurements
obtained from multiple sampling of the same homogeneous
sample under the prescribed conditions. Precision may be considered at
following levels:
Repeatability/System Precision: expresses
the precision under the same operating conditions over a short interval of
time. Repeatability is also termed as intra-assay precision.
intermediate precision: expresses
variations within laboratories, such as different days, different analysts,
different equipment, and so forth.
Ruggedness/Reproducibility: expresses the
precision between laboratories (collaborative studies usually applied to
standardization of methodology).
Accuracy/ % Recovery:
The closeness of agreement between the conventional
true value or an accepted
reference value and the value found. Accuracy can also
be described as the extent to which test results generated by the method and
the true value agree.
Linearity:
Method’s ability (within a given range) to obtain test
results that are directly proportional to the concentration (amount) of analyte
in the sample.
Linearity may be demonstrated directly on the test
substance (by dilution
of a standard stock solution) or by separately weighing
synthetic mixtures
of the test product components.
Range:
The range of an analytical procedure is the interval
from the upper to the lower concentration (amounts) of analyte in the sample
(including these concentrations) for which it has been demonstrated that the
analytical procedure has a suitable level of precision, accuracy and linearity.
The range is normally expressed in the same units as the test results (for example
percentage, parts per million) obtained by the analytical method.
Limit of Detection:
The detection limit of an individual analytical
procedure is the lowest amount of analyte in a sample which can be detected but
not necessarily quantitated as an exact value. The limit of detection (LOD) is
the point at which a measured value is larger than the uncertainty associated
with it. In chromatography, the detection limit is the injected amount that
results in a peak with a height at least two or three times as high as the
baseline noise level.
Limit of Quantitation:
The limit of quantitation (LOQ) of an individual
analytical procedure is the lowest amount of analyte in a sample which can be
quantitatively determined with suitable precision and accuracy. The
quantitation limit is a parameter of quantitative assays for low levels of
compounds in sample matrices, and is used particularly for the determination of
impurities or degradation products.
The quantitation limit is generally determined by the
analysis of samples with known concentrations of analyte and by establishing
the minimum level at which the analyte can be quantified with acceptable
accuracy and precision
Ruggedness:
The degree of reproducibility of results obtained under
a variety of conditions, such as different laboratories, analysts, instruments,
environmental conditions, operators and materials. Ruggedness is a measure of
the reproducibility of test results under normal, expected operational
conditions from laboratory to laboratory and from analyst to analyst.
Ruggedness is determined by the analysis of aliquots from homogeneous lots in
different laboratories.
Robustness:
The robustness of an analytical procedure as a measure
of its capacity to remain unaffected by small, but deliberate variations in method
parameters. It provides an indication of the procedure’s reliability during
normal usage.
Robustness tests examine the effect that operational
parameters have on
the analysis results.
Solution Stability:
Chemical compounds can decompose prior to
chromatographic investigations, for example, during the preparation of the
sample solutions, extraction, cleanup, phase transfer or storage of prepared
vials (in refrigerators or in an automatic sampler). Under these circumstances,
method development should investigate the stability of the analytes and
standards. It is a measure of the bias in assay results generated during a
preselected time interval, for example, every hour up to
46 hours, using a single solution.
Revalidation of Analytical method:
Analytical methods require revalidation if:
The method parameters have to be changed to maintain
the original
performance and the change is outside the tolerance
limits.
New compounds are analyzed that are not within the
method’s original
Scope.
The sample matrix changes.
Any such modification should be documented following a
change control
procedure and the method should be revalidated. As part
of the procedure
the reason for the change should be defined and the
change should be
authorized for implementation and documented.
Performance tests should
Note: Protocol shall be changed as per vendor
requirements for above parameters.
AMV Reference taken
from ICH, WHO & USP.
