# Stability of Daptomycin in Dextrose and Icodextrin-Based Peritoneal Dialysis Solutions

## TL;DR

This study tested how long daptomycin stays stable in different peritoneal dialysis solutions to help guide its clinical use.

## Contribution

The study provides new stability data for daptomycin in icodextrin-based and high-dextrose dialysis solutions.

## Key findings

- Daptomycin was stable for 48 hours in dextrose 2.5% at maintenance levels.
- At loading levels, daptomycin remained stable for 12 hours in dextrose 2.5% and 48 hours in icodextrin 7.5%.
- Stability in icodextrin-based solutions supports its use in patients requiring icodextrin exchanges.

## Abstract

Background: With emerging antibiotic resistance, many patients on peritoneal dialysis require newer antibiotic treatment such as daptomycin. Inadequate clinical information exists across different peritoneal dialysis solutions, including icodextrin, for the stability of intraperitoneal daptomycin. To guide the clinical practice of intraperitoneal daptomycin treatment, we need to establish the stability of daptomycin at dextrose concentration higher than 1.5% and icodextrin, as well as the duration of stability.

Methods: We tested the stability of daptomycin in three types of peritoneal dialysis bags (UltraBag dextrose 2.5%, UltraBag icodextrin 7.5%, and Stay-Safe Balance 2.3%). Daptomycin was reconstituted with water for injection (50 mg/mL), followed by administration to peritoneal dialysis bags to obtain the final daptomycin concentrations of 70 μg/mL (equivalent to 140 mg/2L, the maintenance level) and 245 μg/mL (equivalent to 490 mg/2L, the loading level). The bags were then placed at ambient temperature (25°C) followed by withdrawing 5 mL samples at 0, 4, 8, 12, 24, and 48 h for UltraBag dextrose 2.5% and UltraBag icodextrin 7.5% and 0, 4, 8, 12, and 24 h for Stay-Safe Balance 2.3%. The concentrations of daptomycin in the collected samples were quantified by high-performance liquid chromatography with diode array detector (HPLC-DAD).

Results: Under ambient condition, daptomycin was stable at maintenance level in UltraBag dextrose 2.5% for 48 h and in UltraBag icodextrin 7.5% or Stay-Safe Balance 2.3% for 24 h. For loading level, daptomycin was stable in UltraBag dextrose 2.5% and Stay-Safe Balance 2.3% for 12 h and in UltraBag icodextrin 7.5% for 48 h.

Conclusions: Current stability results support and guide the use of intraperitoneal daptomycin in different dialysis solutions. Patients with peritonitis requiring icodextrin exchange and assisted preparation of daptomycin can benefit from nurses who provide daily home visit based on our stability results.