Comparison of Propofol Microbial Contamination Following Treatment With Drug Disposal Devices

Background: Pharmaceutical waste represents a major burden to the health care system and environment. Proper drug waste disposal devices are vitally needed, especially for propofol solutions that inherently carry a high risk of microbial contamination. Objectives: The aims of this study were to compare the capabilities of 2 drug disposal systems for decontamination of propofol solutions inoculated with medical pathogens and assess chemical degradation of propofol after treatment with Fenton reagents. Methods: Standard microbiological assays were used to assess survival and growth of Escherichia coli and Candida albicans inoculated into propofol solutions. Both a prototype instrument and a commercially marketed disposal device were tested for their ability to kill microbial growth. Furthermore, a propofol bioanalytical assay utilizing high-performance liquid chromatography (HPLC) was developed to measure propofol concentrations before and after treatment with a Fenton reagent cocktail (iron and hydrogen peroxide). Results: Propofol emulsion and diluted solutions lack antimicrobial properties and support the growth of microbes. The prototype instrument effectively killed E. coli and C. albicans inoculated into propofol solutions, while the commercial product did not kill or inhibit the growth of the microorganisms. Finally, propofol was chemically degraded to undetectable quantities (< 0.13 ppm) upon exposure to Fenton reagents in a prototype instrument. Conclusions: We show for the first time that propofol solutions inoculated with microbes are decontaminated upon exposure to Fenton reagents. Treatment with Fenton reagents also chemically destroys the propofol molecule. These results will support the development of novel drug disposal devices for real-time application in the pharmacy setting.