Testing the glass material to predict delamination in pharmaceutical glass containers

Glass delamination is a huge obstacle to the safe delivery of injectables handed out in borosilicate containers. The root causes of delamination are the intrinsic nature of the glass itself and the conversion process of the glass tube into containers. While the conversion process can be improved by appropriate control of its parameters, the composition of the available borosilicate glass can vary within a narrow range. Up to now the delamination propensity of pharmaceutical containers has been predicted on the basis of tests carried out on the container itself. In the present study the focus was placed on the raw glass tubing which is thermally treated and tested by a conventional delamination test. Results for extracted silica were used to establish a correlation between glass strips of the raw tubes and the corresponding vials which were known to delaminate. Glass slabs obtained from experimental melting on lab-scale of glasses of variable compositions, including aluminosilicates, were thermally treated, tested as above and compared with the reference glass. Important information on the delamination propensity of glass as a material can be achieved without the need to have it in tubular form and eventually container form.