Tubular vs. Molded Glass Vial Alkaline Products Delamination Comparative Studies

Abstract

Tubular and molded glass vials are widely used as primary packaging materials for parenteral products, each offering distinct advantages and limitations in relation to chemical durability and delamination behavior. Tubular vials generally provide superior surface uniformity, dimensional accuracy, and overall chemical resistance, making them suitable for high-value and sensitive formulations. However, the high-temperature forming process can lead to localized compositional variations, increasing the risk of delamination at critical regions such as the base and shoulder.
In contrast, molded vials are produced through a single-step forming process that enables better redistribution of volatile components, resulting in improved structural homogeneity and reduced susceptibility to localized delamination. Despite this advantage, molded glass may exhibit comparatively lower hydrolytic resistance and can be more vulnerable to uniform surface corrosion when exposed to alkaline formulations.
Glass delamination is influenced by multiple factors, including formulation pH, buffer composition, glass chemistry, sterilization processes, and storage conditions. Alkaline products, particularly those containing phosphate or citrate buffers, significantly increase the risk of glass surface degradation. Preventive approaches such as surface treatments, appropriate glass selection, and the use of alternative materials like COC/COP or advanced coatings can mitigate these risks.
Overall, the selection between tubular and molded vials should be guided by product-specific requirements, balancing performance, stability, and cost considerations to ensure optimal container–product compatibility.