AVS 59th Annual International Symposium and Exhibition
    Applied Surface Science Tuesday Sessions
       Session AS+BI-TuM

Paper AS+BI-TuM3
The Application of XPS to the Study of Protein Lyophilizates

Tuesday, October 30, 2012, 8:40 am, Room 20

Session: Practical Surface Analysis
Presenter: S.J. Coultas, Kratos Analytical Ltd, UK
Authors: S.J. Coultas, Kratos Analytical Ltd, UK
J.D.P. Counsell, Kratos Analytical Ltd, UK
A.J. Roberts, Kratos Analytical Ltd, UK
S.J. Hutton, Kratos Analytical Ltd, UK
C.J. Blomfield, Kratos Analytical Ltd, UK
R. Geidobler, Ludwig-Maximilians-University, Germany
G. Winter, Ludwig-Maximilians-University, Germany
Correspondent: Click to Email
Long term storage of proteins is most often achieved by freeze drying (lyophilization). For this to be successful it is essential that the process retains the stability and biological activity of the protein. Despite its widespread use there are still problems associated with the process, not least the aggregation of the protein at the ice/liquid interface which develops during the freezing stage. To overcome this problem excipients are commonly used to ease the stresses at this interface and stabilise the protein. Polysorbates are commonly used for this purpose but there has been recent interest in using other excipients.

X-ray photoelectron spectroscopy (XPS) is ideally suited to the study of these materials due to its surface sensitivity (1-10 nm) and the quantitative nature of the data.

In this study we use XPS to investigate the protein stabilisation mechanism in lyophilizates produced using different excipients. We show there to be clear differences in the surface chemistry of the resultant lyophilizates. We also investigate the effect of temperature on the protein surface chemistry and stability.