Laboratory intercomparison for the evaluation of the delamination propensity of glass containers for pharmaceutical use

This paper is the result of two round robin activities run by the Technical Committee TC12, Pharma Packaging, of the International Commission on Glass (ICG). It deals with the phenomenon of delamination, that is, the formation of lamellae or flakes in drug products due to specific and localized corrosion of glass vials, and it follows a first paper PDA J Pharm Sci Technol. 2018, 72, 553–565where a testing protocol for the evaluation of the delamination propensity was proposed. The results showed that the protocol gives information on the quality of vials with respect to the propensity to corrosion, but no direct correlation with delamination could be demonstrated, as no lamellae formation was observed. In response, further testing was carried out on five sets of vials with expected low delamination propensity, compared to a set of vials with high expected delamination propensity using both the proposed protocol and a more aggressive protocol. The objective was to observe lamellae at least in the high propensity vials to show a correlation to initial test protocols. The results show that there is a very good consistency between the results of the two testing protocols and therefore, with a good level of reliability, the degree of glass surface corrosion can be estimated by the testing protocol proposed by the Technical Committee. In some cases, the glass surface corrosion results may indicate an increased risk of delamination (depending on the individual interaction between the pharmaceutical solution and the inner vial surface).