Impact of Vial Washing and Depyrogenation on Surface Properties and Delamination Risk of Glass Vials.

Abstract

The proper understanding of glass delamination is important to glass manufacturers, pharmaceutical companies, and health authorities to mitigate the occurrence of glass flakes from the vial when in contact with specific drug product solutions. The surface of glass vials is altered during glass cane- and vial forming processes and is exposed to different stress conditions during drug product processing before coming in contact with the drug product solution. In this study, the impact of vial washing and depyrogenation including an evaluation of various residual water volumes on surface properties of glass vials was investigated for a defined set of vials. 3D laser scanning microscopy was established as a new method for topographic analysis of curved surfaces of glass vials operating in high-throughput mode. A subset of vials was subsequently exposed to delamination stress testing and both the stressed solution and inner vial surface were analyzed by a panel of conventional and advanced analytical techniques including 3D laser scanning microscopy. The data showed that vial washing and depyrogenation strongly influenced surface properties, in particular those of uncoated vials. Surface characteristics such as pits increased depending on the process conditions, which especiallyapplies toExpansion 33 vials. Even low residual water volumes of 50μL after vial washing were sufficient to change the surface properties of the glass and weaken the surface in those positions prone to glass delamination. An increase in pits was related to a greater risk for glass delamination. Vial processing conditions need to be assessed when aiming at minimizing the glass delamination risk during parenteral product storage.