Stability of reconstituted methohexital sodium

The purpose of this study was to determine the stability of reconstituted solutions of methohexital sodium over a 6-week period. Stability of methohexital was examined using reversed-phase high-performance liquid chromatography. The results indicate that reconstituted methohexital is extremely stable for up to 6 weeks when stored at 4°C. When stored at room temperature, reconstituted solutions of methohexital contained increasing levels of degradation products and showed a corresponding decrease in methohexital over a 6-week period. However, the rate of degradation of the drug was slow, with less than 10% of the methohexital undergoing breakdown. In addition, tests for microbial contamination of the solutions stored at room temperature and under refrigeration were negative for up to 6 weeks. This study demonstrates that methohexital, when stored under refrigeration for up to 6 weeks, is virtually chemically identical to a freshly reconstituted solution of the drug. When stored at room temperature, there is some degradation of the drug, but it is not known whether the small amount of degradation is clinically significant. This study emphasizes the importance of obtaining scientific data to support changes in guidelines related to handling and storage of drugs.