Following the previously issued draft for USP General Chapter <660> Containers – Glass, the final version of the chapter was published and made official on 1st October 2023. In particular, the revision to General Chapter <660> changed the "composition based" glass type definition to one that is "performance based".
From "composition based" definition to "performance based"
To disconnect the Type designation from the glass composition, in principle all glasses that pass the test for Type I can be used for drugs that require Type I glass as per the packaging section in their monographs.
Previously, <660> defined Type I as borosilicate glass, Type II as treated soda-lime silica, and Type III as soda-lime silica. Now, General Chapter <660> instead defines glass Types I, II, and III by performance characteristics, allowing for additional compositions to be considered Type I, II, and III glass based on their hydrolytic resistance. However, there are no proposed changes to test procedures or acceptance criteria.
In addition, revisions will be made to 14 monographs that currently prescribe a specific glass type by adding the word “preferably” in the packaging section of the monograph. For example, a current monograph that requires “Type I glass” would be revised to state “preferably of Type I glass.” The addition of the word “preferably” to the monographs at issue means that the use of the glass specified is preferred, but not required. This revision will give manufacturers additional flexibility in their choice of packaging and pave the way for new or different types of packaging to be approved (e.g. aluminosilicate glass).
It is important to notice that the two compendial chapters - USP <660> Containers – Glass and Ph. Eur. 3.2.1 Glass containers for pharmaceutical use - are curently not harmonized in this point. The Ph. Eur. still refers to borosilicate glass ("neutral glass") for Type 1 glass containers.
For more information please see USP Chapter <660> Containers – Glass.