Physical sciences and materials

Type I Borosilicate Glass

Type I borosilicate glass is a pharmaceutical primary-packaging glass classified under USP General Chapter , Containers—Glass, as meeting the highest hydrolytic-resistance category through borosilicate composition and a passing result on the chapter's powdered glass test. A glass lot or container qualifies for the 'USP Type I' designation only once tested and documented under this method — borosilicate composition is necessary but not sufficient on its own; the designation follows from a specific tested result, not from raw material alone. It is distinct from the general-purpose term 'borosilicate glass' used for laboratory apparatus under ASTM E438, a different standard that covers non-pharmaceutical labware such as beakers and flasks.