Microstructural Phase Separation And Delamination In Glass For Pharma Applications

Flaking or peeling of inner glass container wall, teamed "delamination", has been observed in Type I borosilicate glasses due to long term storage of some parenteral drugs and has been the reason for several drug recalls in recent years. While there may be different types of delamination phenomena, it is suggested that the dominant precursor to delamination is the well-known microstructural phase separation in borosilicate glasses and the subsequent preferential dissolution of the lesser chemically durable phase by corrosive medicines. Hence, processing of glass during container forming or minor composition changes that tend to keep glass out of the immiscibility dome should help reduce such issues. Introduction of a high surface compression in the glass container by chemical strengthening may also have beneficial effect by requiring a higher tensile stress for crack propagation during peeling.