Assessing the stability of daptomycin in icodextrin-based peritoneal dialysis solution

Background: The stability of antimicrobials in peritonitis during peritoneal dialysis (PD) solutions is a critical factor influencing treatment success. This study investigated the stability of daptomycin (DAP) when combined with icodextrin-based PD solution, by measuring DAP concentrations and observing any structural changes. Methods: A dose of DAP (350 mg) was dissolved in 7 mL of saline in a clean bench. The solution was then injected into the large compartment (1,260 mL) of NICOPELIQ^® Peritoneal Dialysis Solution and thoroughly mixed. Samples were collected at intervals ranging from 0 to 336 h (7 points in total). The concentration of DAP was quantified using high-performance liquid chromatography (HPLC). The structure of any unidentified peaks was determined using HPLC coupled with electrospray ionization tandem mass spectrometry. Results: DAP maintained 90% of the initial concentration in NICOPELIC^® for 72 h at room temperature and 12 h at 37 °C. Unidentified peaks, distinct from DAP, were detected during analysis. Further investigation indicated that these peaks corresponded to anhydrated DAP. Conclusions: The findings from this stability study are expected to enhance the effectiveness of outpatient management and preparation for treating peritonitis using DAP.