Why is disodium edetate or sodium metabisulfite added to formulations of propofol?

Disodium edetate and sodium metabisulfite are added to formulations of propofol primarily to inhibit bacterial growth. These compounds serve as preservatives, which are critical in preventing microbial contamination in injectable drug products. Given that propofol is an intravenous anesthetic, it is essential to maintain its sterility to ensure patient safety and efficacy of the medication.

While enhancing drug solubility or adjusting pH might be relevant in some contexts for drug formulations, the specific role of disodium edetate and sodium metabisulfite in propofol formulations is to act as bacteriostatic agents, preventing bacteria from proliferating. This function is particularly important for maintaining the integrity and safety of the product throughout its shelf life and after the vial has been opened, as these products may be stored for some time before use.