Improvement of the decision efficiency of the accuracy profile by means of a desirability function for analytical methods validation -: Application to a diacetyl-monoxime colorimetric assay used for the determination of urea in transdermal iontophoretic extracts

Validation of analytical methods is a widely used and regulated step for each analytical method. However, the classical approaches to demonstrate the ability to quantify of a method do not necessarily fulfill this objective. For this reason an innovative methodology was recently introduced by using the tolerance interval and accuracy profile, which guarantee that a pre-defined proportion of future measurements obtained with the method will be included within the acceptance limits. Accuracy profile is an effective decision too] to assess the validity of analytical methods. The methodology to build such a profile is detailed here. However, as for any visual toot it has a part of subjectivity. It was then necessary to make the decision process objective in order to quantify the degree of adequacy of an accuracy profile and to allow a thorough comparison between such profiles. To achieve this, we developed a global desirability index based on the three most important validation criteria: the trueness, the precision and the range. The global index allows the classification of the different accuracy profiles obtained according to their respective response functions. A diacetyl-monoxime colorimetric assay for the determination of urea in transdermal iontophoretic extracts was used to illustrate these improvements. (C) 2007 Elsevier B.V. All rights reserved.