Measurement uncertainty from validation and duplicate analysis results in HPLC analysis of multivitamin preparations...

An approach to calculate the measurement uncertainty in the HPLC analysis of several hydro- and liposoluble vitamins in multivitamin preparations with different galenic composition and properties is described. In the first instance it is examined if duplicate analysis results, obtained with a fully validated analysis method on different lots of an effervescent tablet preparation spread over several points of time, might contribute to calculate the measurement uncertainty of the HPLC method used and if the established uncertainty is acceptable in the assessment of compliance with the legal content limits. Analysis of variance (ANOVA) and precision calculations, based on the ISO 5725-2 norm are applied on the analysis results obtained to estimate precision components, necessary to derive the measurement uncertainty. In the second instance it is demonstrated to which extent the fully validated method of analysis for effervescent tablets is applicable to other galenic forms as e.g. capsules with oily emulsions, tablets, coated tablets, oral solutions, em leader and which specific modifications in the analysis steps are involved. By means of duplicate analysis results, acquired from a large series of real samples over a considerable period of time and classified according to their similarity in content, galenic forms and matrices, estimations of measurement uncertainty calculations are shown.