Stability of cefazolin sodium in peritoneal dialysis solutions

The stability of cefazolin sodium was studied in two commonly used peritoneal dialysis solutions. Cefazolin (as the sodium salt) 250 mg was added to 500-mL bags of dialysis solution containing 1.5% or 4.25% dextrose injection to yield a target concentration of 0.5 mg/mL. Of 18 bags containing 1.5% dextrose injection, six were stored at 4 degrees C, six at 25 degrees C, and six at 37 degrees C. Similarly, of 18 bags containing 4.25% dextrose injection, groups of six were stored at each temperature. Samples were measured for cefazolin concentration by high-performance liquid chromatography at 0, 3, 7, 10, and 14 days for solutions stored at 4 degrees C; 0, 1, 2, 3, 8, and 11 days for solutions stored at 25 degrees C; and 0, 6, 12, and 24 hours for solutions stored at 37 degrees C. The cefazolin concentration in both solutions was greater than or equal to 90% of the initial concentration for 14 days at 4 degrees C, 8 days at 25 degrees C, and 1 day at 37 degrees C. On day 11 at 25 degrees C, however, the loss of cefazolin was 11% for the solution containing 1.5% dextrose injection and 15% for the 4.25% dextrose injection. The sterility of the solutions was not determined. Cefazolin sodium was stable in peritoneal dialysis solutions containing 1.5% and 4.24% dextrose injection for 14 days at 4 degrees C, 8 days at 25 degrees C, and 24 hours at 37 degrees C.