Compatibility and stability of cefotaxime, vancomycin, and ciprofloxacin in antibiotic lock solutions containing...

The purpose of this study was to assess the compatibility and stability of drugs commonly found in antibiotic lock solutions (cefotaxime 10 mg/mL plus heparin 5000 IU/mL, vancomycin 25 mcg/mL plus heparin 10 IU/mL, and vancomycin 25 mcg/mL plus ciprofloxacin 2 mg/mL plus heparin 10 IU/mL). Antibiotic lock solutions under investigation were generated in triplicate from pooled starting samples and maintained at 4 degrees Celsius, 27 degrees Celsius, and 40 degrees Celsius. The antibiotic lock solutions were assessed at various time intervals for chemical stability (specified as retaining greater than 90% of initial drug via high-performance liquid chromatographic analysis) and physical stability(specified as solution free of visible precipitates). Antibiotic lock solutions containing cefotaxime plus heparin remained chemically and physically stable at 4 degrees Celsius throughout the study period. However, samples maintained at higher temperatures had no physical instability but underwent significant chemical degradation as early as 24 hours after the beginning of the incubation period. Vancomycin in antibiotic lock solutions with heparin also remained chemically and physically stable at 4 degrees Celsius but underwent minor chemical degradation (with no physical instability) at higher temperatures. Vancomycin and ciprofloxacin in antibiotic lock solutions with heparin demonstrated physical instability at all temperatures by 24 hours. In conclusion, none of the antibiotic lock solutions tested met the chemical and physical stability criteria specified at the beginning of the study. These results suggest that the efficacy of these antibiotic lock solutions is decreased due to chemical or physical instabilities over time.