Pharmaceutical Glass Interactions: A Review of Possibilities

Glass is used as packaging material for parenteral formulation from years. Various untoward occurrences have observed over the period of time with glass containers which leads to therapeutic failures or even toxicity to the patients. Glass has been the primary choice for packaging of parenteral formulations, unexpected degradation or product losses during stability have forced many researchers to evaluate the underlying mechanisms leading to a larger understanding of some of the untoward properties of glass. Oxides of various metal ions viz. aluminium, arsenic, barium, iron etc. are added in glass to modify its physicochemical properties based on specific requirements. Metal ions could leach from the glass structure due to several reasons and could lead to generation of particulate matter, could cause metal ion toxicity or act as catalyst to hasten drug degradation. Delamination or formation of glass flakes is one of the major problems currently under high scrutiny by the regulators. Similarly, some molecules have an affinity to adsorb to glass leading to a low potency in the administered drug. Interaction between glass and drug product depends upon composition/type of glass, processing of glass and formulation variables such as pH, buffer, properties of drug, sterilization cycles, storage conditions etc. This review describes several possible means of interaction of glass and drug product encountered by researchers under a gamut of conditions.