1.0 OBJECTIVE:
To lay down the procedure for Specificity for Assay Method
2.0 SCOPE:
This SOP is applicable for Specificity for Assay Method in company Name.
3.0 BACKGROUND:
NIL
4.0 RESPONSIBILITY:
4.1 All Analytical research personnel shall follow the SOP.
4.2 Group leader of Analytical research shall ensure the procedures to be followed.
4.3 Head Analytical research or his designee to ensure overall compliance.
5.0 PROCEDURE:
5.1 ICH
defines “ Specificity is the ability to assess unequivocally the
analyte in the presence of components which may be expected to be
present. Typically these might include impurities, degradants, matrix,
etc.”
5.2 That means that the analyte of interest can be identified even in the presence of other components such as impurities, degradants and others in the solution.
5.3 In the Chromatographic analysis, this can
be identified by observing the retention times of the analyte,
impuruties and degradants etc.... and also the resolution between the
two closely eluting peaks.
5.4 For example the major analyte RT at 10.880 min, AntiIsomer is at 11.818 and Lactone Impurity is at 17.551 min and the resolution between the closest eluting peak to the major peak and AntiIsomer is 2.08.
5.5 In
cases where a non-specific assay is used, other supporting analytical
procedures should be used to demonstrate overall specificity. For
example, where a titration is adopted to assay the drug substance for
release, the combination of the assay and a suitable test for impurities
can be used.
5.6 Impurities are available
For the assay , this should involve
demonstration of the discrimination of the analyte in the presence of
impurities and/or excipients; practically, this can be done by spiking pure
substances (drug substance or drug product) with appropriate levels of
impurities and/or excipients and demonstrating that the assay result is
unaffected by the presence of these materials (by comparison with the assay
result obtained on unspiked samples).
5.6.1 Demonstration of specificity for assay method:
Demonstration
of the specificity of the analyte in the presence of impurities, this
can be done by spiking the pure substance with appropriate (1%, 3% and
5%) levels of the impurities and demonstrating that the Assay result is
unaffected by the presence of these impurities. Compare the results from
unspiked sample.
% Level % Assay Spiked Sample % Assay of Unspiked Sample
Sample +1% spiked 98.97
Sample +3% spiked 98.86 98.98
Sample +5% spiked 98.96
5.6.2 The
demonstration of the specificity of the analyte in the presence of
impurities, this can be done by spiking the pure substance with
appropriate (I%, 3% and 5%) levels of the impurities and demonstrating
that the Assay result is unaffected by considering total weight
(i.e,Drug subsntace and added impurity level) in the presence ofthese
impurities. Compare the result from unspiked sample.
% Level % Assay Without considering % Assay Considering
Impurity weight Impurity weight
Impurity weight Impurity weight
Sample +1% spiked 98.97 97.07
Sample +3% spiked 98.86 93.37
Sample +5% spiked 98.96 90.16
5.7 Impurities are not available
If
impurity or degradation product standards are unavailable, specificity
may be demonstrated by comparing the test results of samples containing
impurities or degradation products to a second well-characterized
procedure e.g.: pharmacopoeial method or other validated analytical
procedure (independent procedure). As appropriate, this should include
samples stored under relevant stress conditions: light, heat, humidity,
acid/base hydrolysis and oxidation.
- for the assay, the two results should be compared;
5.7.1 Eg: Forcibly
degrade Drug Substance sample under elevated temperature, Acid
hydrolysis, Base hydrolysis, photo degradation and oxidation. All stress
solutions should analyse using Photo diode array detector and calculate
the Assay in each stress condition. For stressed conditions final
degraded sample confirmed in the purity by HPLC and that same sample
will be directly analyzed for assay content.
Peak
purity tests may be useful to show that the analyte chromatographic
peak is not attributable to more than one component (e.g., diode array,
mass spectrometry).
6.0 ANNEXURES
Nil
0 Comments