Glass delamination of Type 1 pharmaceutical vials has resulted in an increasing number of recalls over the past several years. The factors leading to surface attack due to the interaction between the drug product and glass surface of filled vials are well documented and include elevated pH (greater than pH8), storage temperature (room temperature as opposed to cold storage), and use of vials constructed of glass tubing (as compared to molded vials). Other factors influencing the chemical resistance and durability are provided in UPS <1660>. Our scientific team has developed a protocol for preparation and examination of glass vials for assessing the interaction of the drug product with the glass. It is noted here that although there are various opinions on what constitutes delamination, the interaction of the product with the glass is not the widely accepted definition of delamination. Rather, it is the formation and detection of glass flakes in the product during visual inspection. The presence of glass particles in a product is also considered the final step in the delamination process. However, the detection of the attack of the glass surface by the drug product, even if no particles are found in the product, can provide an opportunity for a manufacturer to undertake preemptive action at an early stage of the delamination process.
