The United States Pharmacopeia outlines specific qualification tests based upon the type of glass being used. Glass used for pharmaceutical containers is either a borosilicate (neutral) glass or a soda-lime glass. Borosilicate glass contains a significant amount of boric oxide, aluminum oxide, and alkali and/or alkaline earth oxides. Borosilicate glass has a high hydrolytic resistance due to the chemical composition of the glass itself and is classified as Type I glass. Soda lime glass is a silica glass containing alkali metal oxides. Soda-lime glass has a moderate hydrolytic resistance due to the chemical composition of the glass itself and is classified as Type III glass. The inner surface of glass containers may be treated to improve hydrolytic resistance. The treatment of Type III soda-lime glass containers will raise their hydrolytic resistance from a moderate to a high level, changing the classification of the glass to Type II. The outer surface of glass containers may be treated to reduce friction or for protection against abrasion or breakage. The treatment of the outer surface does not come into contact with the inner surface of the container. Glass may be colored to provide protection from light or may have a coating applied to the outer surface. Such containers must meet the requirements for Light Transmission under Containers—Performance Testing <671>. The quality of glass containers is defined by measuring their resistance to chemical attack. In addition, Type I containers for aqueous parenteral preparations are tested for arsenic release.

Relevant USP Glass Testing Procedures Include:

  • USP/NF Section <660> Type I Highly Resistant Borosilicate Glass
    • Hydrolytic Resistance – Glass Grains
    • Surface Glass Test
      • Determine Fill Volume
    • Surface Etching
    • Arsenic USP <211>
    • Light Trasmission (Amber)
  • USP/NF Section <660> Type II Glass – Trated Soda Lime
    • Hydrolytic Resistance – Glass Grains
    • Surface Glass Test
      • Determine Fill Volume
    • Surface Etching
    • Arsenic USP <211>
    • Light Transmission (Amber)
  • USP/NF Section <660> Type III Glass
    • Hydrolytic Resistance – Glass Grains
    • Surface Glass Test
      • Determine Fill Volume
    • Light Transmission (Amber)

Relevant European Pharmacopeia Testing:

  • EP 3.2.1 Glass Containers for Pharmaceutical Use

Whitehouse Laboratories operates a “Container Testing Center of Excellence”. The entire business unit brings multiple levels of experience to each container testing program. Staff members with specific areas of expertise are always available to consult on your testing needs.