Method validation experiment

Table 2 Matrix-study combinations for which method validation experiments are needed...

The method validation experiments should be well planned and laid out to ensure efficient use of time and resources during execution of the method validation. The best way to ensure a well-planned validation study is to write a method validation protocol that will be reviewed and signed by the appropriate person (e.g., laboratory management and quality assurance). 

System suitability is part of method validation. Experience gained during method development will give insights to help determine the system suitability requirements of the final method. An example is the hydrolysis of acetylsalicylic acid to salicylic acid in acidic media. Separation of this degradation peak from the analyte could be one criterion for the system suitability of an acetylsalicylic acid assay. 

Method Procedure. Since the method procedure is undergoing constant modifications during method development, it is very important to define the procedure before method validation. This will ensure that the same method procedure will be used in all method validation experiments. 

System Suitability Tests. The appropriate system suitability tests should be defined before method validation (e.g., precision, resolution of critical related substances, tailing, detector sensitivity). These system suitability tests should be performed in each method validation experiments. System suitability results from the method validation experiment can be used to determine the appropriate system suitability acceptance criteria. 

System suitability. During the robustness testing of method validation, critical method parameters such as mobile phase composition and column temperature are varied to mimic the day-to-day variability. Therefore, the system suitability results from these robustness experiments should reflect the expected range for the system suitability results. As a result, system suitability results in these method validation experiments are very useful in determining the system suitability... 

A spiked sample is a sample prepared by adding a known quantity of analyte to a matrix which is close to or identical to that of the sample of interest. Spiked samples may be used in method validation experiments to help identify matrix effects and determine the recovery (see Section 2.3) of an analyte or the selectivity of the method. 

In this section, three categories of experimental design are considered for method validation experiments. An important quality of the design to be used is balance. Balance occurs when the levels each factor (either a fixed effects factor or a random effects variance component) are assigned the same number of experimental trials. Lack of balance can lead to erroneous statistical estimates of accuracy, precision, and linearity. Balance of design is one of the most important considerations in setting up the experimental trials. From a heuristic view this makes sense, we want an equivalent amount of information from each level of the factors. 

Table 2.5 Experimental Domain for a Dissolution Method Validation Experiment... 

The recommendations on design of method validation experiments contained in this chapter represent the authors assessment of current best practices, and these should be considered in the context of any subsequent guidance that may be provided by lUPAC or other authoritahve scientific bodies. As guidance is constantly evolving, it is important that a check be undertaken to ensure that the most recent relevant guidance is consulted before planning any method validation studies. 

Traditional method-validation experiments described by ICH and the harmonized lUPAC guidelines provide a reasonable assurance that the method performs as needed. However, these guidelines do not recommend establishing criteria for total method variability nor do they directly answer the question of risk and agreement of a sample measurement with... 

---