Pre-study and in-study validation of a size-exclusion chromatography method with different detection modes for the...

Size exclusion chromatography (SEC) with different detection modes was assessed as a means to characterize the type of bevacizumab aggregate that forms under thermal stress, quantitatively monitoring the aggregation kinetics. The combination of SEC with light-scattering (SEC/LS) detection was validated using in-study validation process. This was performed by applying a strategy based on a control chart to monitor the process parameters and by inserting quality control samples in routine runs. The SEC coupled with a differential refractive-index detector (SEC/RI) was validated using a pre-study validation process in accordance with the ICH-Q2 (R1) guidelines and in-study monitoring in accordance with the Analytical Target Profile (ATP) criteria. The total error and β-expectation tolerance interval rules were used to assess method suitability and control the risk of incorrectly accepting unsuitable analytical methods. The aggregation kinetics data were interpreted using a modified Lumry-Eyring model. The true order of the reaction was determined using the initial-rate approach. All the kinetic data show a linear Arrhenius dependence within the studied temperature range. The Arrhenius approach over-predicted the aggregation rate for 5°C, but provides an idea of the aggregation process and amount of aggregate formed. In any case, real-time stability data are necessary to establish the product shelf-life.