Raphael Bar

A statistical analysis for determining an expiration date can be applied to replicates or their corresponding averages as suggested in industry guidelines.

This paper demonstrates how assay data sets of a formulated liquid product, drug substance, and an impurity, obtained from combined accuracy-precision studies, are evaluated to calculate statistical intervals (prediction and tolerance intervals) and to graphically display the total analytical error (TAE) to account for the systematic and random errors.

Part two of this article series shows how traditional statistical process control rules can be relaxed or adjusted to allow charting and evaluation of real-life data of pharmaceutical processes with a reduced number of false alarms.

Part 1 of this article series demonstrates, using real-world process data, that the four fundamental assumptions underlying the classical Shewhart control charts—randomness, independence, constant average, and constant variation—are often not met.