Fundamental guidelines according to the ICH

Type of analytical procedure characteristics Identification Testing for impurities Quantitation Limit Assay dissolution (measurement only) content/ potency 

The various concepts used in the assessment of analytical results are defined below and methods for determining them are recommended [146]. 

Definition The trueness or accuracy of an analytical method is given by the extent to which the value obtained deviates from the true value. It is often expressed as the amount determined by analysis expressed as a percentage of the known amoimt of active ingredient added to the matrix material. It is a measure of the exactitude of the method. 

Determination The trueness or accuracy of a method can be determined by using it to analyze specially prepared samples. In these, the active ingredient is added in a similar concentration to that expected in the pharmaceutical product and also in somewhat higher and lower concentrations. The accuracy is then calculated as a % recovery. 

Definition The precision of an analytical method is the extent of the agreement between the measured values in a series of analyses of a homogeneous sample. The precision of a method is normally given by the standard deviation (.S ) or relative standard deviation (coefficient of variation or. Srei). The precision is a measure of the variabUity of the analytical method under normal laboratory conditions. 

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