Stability and compatibility of anakinra with ceftriaxone sodium injection in 0·9% sodium chloride or 5% dextrose injection

The stability and compatibility of anakinra (recombinant human interleukin‐1 receptor antagonist) with ceftriaxone sodium in 0·9% sodium chloride or 5% dextrose injection was determined during a 4‐h period at ambient room temperature and light. Anakinra was diluted in 0·9% sodium chloride or 5% dextrose to the concentrations of 4 and 36 mg/ml. Anakinra, at each concentration was mixed with ceftriaxone sodium (20 mg/ml) in a 50 : 50 proportion and stored in plastic culture vials with polypropylene caps. The samples were collected at 0, 2 and 4 h after mixing. Anakinra and ceftriaxone concentrations were measured using stability‐indicating HPLC methods.
In 0·9% sodium chloride injection, the mean concentrations of anakinra and ceftriaxone exceeded 98% of initial concentrations at the end of the study period. In 5% dextrose, however, anakinra concentrations were below 90% of the expected initial concentration at the time of first analysis (within 0·5 h). Thus, anakinra appears to be stable and compatible with ceftriaxone sodium when diluted in 0·9% sodium chloride injection, but not in 5% dextrose injection over 4 h at ambient room temperature and light.