New investigations into the stability of Mesna using LC-MS/MS and NMR.

INTRODUCTION It is important for sarcoma patients to receive the correct dose of Mesna as an adjuvant with ifosfamide to reduce the risk of hemorrhagic cystitis. This paper describes a study conducted to evaluate the physicochemical stability of Mesna for injection formulation over 14 days. METHODS Mesna samples (n = 4, 20 mg/ml) were incubated in glass vials at 37 + 0.5ºC. Mesna concentrations were determined by liquid chromatography-mass spectrometry (LC-MS/MS), and nuclear magnetic resonance spectroscopy (NMR) was used to detect degradation products. Evaporative losses and pH were also monitored. RESULTS Our results differed from those published in existing literature. Both LC-MS/MS and NMR indicated that Mesna was unstable. The mean percentage decrease in Mesna concentration was 40% by day 14 of the analysis. The presence of Mesna's dimer Dimesna was detected on day 0 and its concentration increased over time. Dimesna was the only by-product identified. CONCLUSION Both LC-MS/MS and NMR analyses confirmed the instability of Mesna and its conversion into Dimesna.