USP introduces New Glass Materials

The USP Packaging and Distribution Expert Committee (PDEC) proposes to revise the following two USP glass chapters:

• <660> Containers - Glass (New proposed title: Glass Packaging Systems and their Materials of Construction)
• <1660> Evaluation of the Inner Surface Durability of Glass Containers (New proposed title: Glass Containers used in Pharmaceutical Packaging/Delivery Systems—Manufacture and Evaluation of the Inner Surface Durability)

The two draft chapters have been published in Pharmacopeial Forum PF 50(5). They are open for comment until 30 November 2024.

Proposed Changes and Addition of New Glass Materials

The USP PDEC is issuing a revision to chapter <660> to enhance the evaluation and standards for glass packaging systems. The proposed changes include the addition of new glass materials, the removal and replacement of outdated tests, and the revision of existing methodologies to ensure better safety, efficacy, and performance of glass packaging in pharmaceutical applications. The key changes being proposed are the following:

• Two new glass materials have been introduced—aluminosilicate glass and quartz glass. The previous revision to General Chapter <660> already changed the "composition based" glass type definition to one that is "performance based".
• The Glass Grains Test has been removed and replaced with a new identification test based on Elemental Composition by Wavelength Dispersive X-Ray Fluorescence. According to the USP, this "modern method enhances the accuracy of identifying and characterizing glass materials".
• The Surface Etching Test has been eliminated, streamlining the testing process and removing redundancies.
• The Determination of Inner Surface Hydrolytic Resistance test is retained with added guidance on the application of autoclave instructions based on new studies. 
• A new extractable arsenic test has been added using inductively coupled plasma (ICP) technology, providing a more sensitive and accurate measurement of arsenic levels.
• The Spectral Transmission Test for Colored Glass Containers has been revised, incorporating data from both borosilicate and soda–lime–silica colored glass to refine the evaluation of light protection capabilities.

In addition, the supporting general information chapter <1660> is also being revised. The PDEC is proposing to revise this chapter to support the revision of chapter <660>. The revised chapter <1660> provides comprehensive guidelines on the formation, processing, and testing of glass containers used in pharmaceutical packaging. It covers various glass types, including aluminosilicate, borosilicate, quartz, and soda–lime–silica glass. Key topics include:

• Glass composition
• Formation processes
• Surface treatments
• Factors affecting inner surface durability

The chapter also introduces screening methods to detect glass particles and flakes, ensuring the durability and safety of glass containers. It emphasizes the importance of collaboration between pharmaceutical manufacturers and glass suppliers to maintain high-quality standards throughout the glass supply chain.

For more information please visit the Pharmacopeial Forum.