When prepared as directed, reconstituted and infusion solutions of pemetrexed contain no antimicrobial preservatives. Chemical and physical in-use stability of reconstituted and infusion solutions of pemetrexed were demonstrated for 24 hours at refrigerated temperature. From a microbiological point of view, the product should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user and would not be longer than 24 hours at 2°C to 8°C.1

Discard any unused portion. Pemetrexed is not light sensitive.2

Where reconstituted solutions of pemetrexed cannot be stored under refrigerated conditions for a certain period, Lilly advises customers to follow the USP guidance for low-risk compounded sterile preparations, prepared under aseptic technique (ISO Class 5 or cleaner air), which allows for the storing of reconstituted solutions such as pemetrexed at controlled room temperature for up to 6 hours in the vial and 12 hours in the infusion solution (for a total of 18 hours).3,4

Although a stability study demonstrated that pemetrexed solutions were physically and chemically stable when stored in polypropylene syringes at room temperature for 2 days and when refrigerated for 31 days, this study did not address bacteriologic concerns.5 Therefore, storage should be limited to the manufacturer-recommended 24 hours under refrigeration.1

Although chemical stability is unaffected, a substantial amount of microparticulates may form if pemetrexed diluted in infusion solutions is stored under refrigeration in PVC bags for longer than 24 hours.6 Therefore, storage should be limited to the manufacturer-recommended 24 hours under refrigeration.1

Although chemically stable, freezing of pemetrexed admixtures in PVC bags should be avoided due to the large number of microparticulates formed. Therefore, previously frozen pemetrexed solutions should not be used.7