Effect of freezing, long-term storage, and microwave thawing on the stability of cefepime in 5% dextrose infusion polyvinyl chloride bags.

Cefepime is often used in antibiotic infusions for the hospitalized patients. Using intravenous solutions of cefepime prepared in advance can be efficient, but little information is available about the stability of that antibiotic after freezing followed by microwave thawing. The purpose of this study was to investigate how freezing, long-term storage, and microwave thawing can affect the stability of cefepime in 5% dextrose injection. The stability of 5 polyvinyl chloride bags of solution containing 2g of cefepime per 100 mL of 5% dextrose injection was studied after the bags had remained frozen for 1 month at -20 deg C, were thawed in a microwave oven with a validated cycle, and were stored at 4 deg C. The concentration of cefepime was measured by high-performance liquid chromatography by means of a reversed phase column, a mobile phase consisting of 10% acetonitrile and pentane sulfate buffer, and ultraviolet detection at 254 nm with a diode array detecor. Visual inspection was also conducted, and pH measurements were obtained. No color change or precipitation in the solution was observed. Cefepime remained stable for 11 days. During this period, the 95% lower confidence limit of the estimated regression line of the concentration-time profile remained above 90% of the initial concentration and the pH value increased slightly without affecting chromatographic parameters. Within those limits, cefepime may be prepared in advance by a centralized intravenous admixture service; it may be frozen and then thawed in a microwave before use in clinical units.