Method Validation Question

[wjet]

I am developing a test method for a pharmaceutical analyte that will calculate its purity by simply monitoring the % area of the primary peak within the chromatogram. Can anyone offer suggestions as to which of the usual validation parameters can/should be employed in validating a % area test method?

[tom jupille]

First and foremost: specificity. In the case you are proposing, you should establish that the response factor for you analyte is comparable (ideally, identical) to the response factors of likely impurities/contaminants. For system suitability, I would look at resolution from the closest impurity/contaminant and tailing factor. The rest is pretty much standard: linearity, accuracy (recovery), precision, etc.