Ion-exchange enhancement of borosilicate glass vials for pharmaceutical packaging

Abstract

Pharmaceutical containers for parenteral use, including vials, ampoules, prefilled syringes, and cartridges, are traditionally made of glass. However, the most commonly used type, borosilicate glass, is susceptible to issues such as breakage, corrosion, and delamination, which can jeopardize the safety and efficacy of the enclosed drugs. To address these concerns without compromising the visual or qualitative aspects of borosilicate medical glass vials, this study aimed at the enhancement of their mechanical, chemical, and corrosion resistance. A single ion exchange treatment (IET) in a salt bath of molten KNO₃ at temperatures of 400, 450, and 500 °C for 2, 12, and 24 h was applied. The effects of the ion exchange process performed under different conditions were assessed by measuring Vickers hardness, crushing load, and chemical durability. The mechanical load required to crush full-body vials after the ion exchange process at 500 °C for 2, 12, and 24 h showed an increase in the applied force values (1650 ± 80, 2340 ± 80, and 2325 ± 40 N) compared to untreated vials (1157 ± 20 N).

No radial cracks were observed on the surface of treated glass vials after indentation, indicating the presence of compressive stresses that prevented the initiation and propagation of cracks. The EDS analysis confirmed an increase in potassium concentration and a decrease in sodium content near the surface of samples modified by ion exchange treatment. The treated samples showed appropriate chemical stability in different acidic, basic, and neutral solutions. Conspicuous changes are noticed in the Raman spectra after IET, specifically in the Q_n species region. The results indicate the potential of the ion exchange treatment in enhancing the properties of borosilicate glass vials by relatively simple and easily scalable techniques.