Room temperature stability of injectable succinylcholine dichloride

The purpose of this study was to determine the room temperature stability over a period of several months of commercially available intravenous succinylcholine dichloride (Quelicin, 20 mg/mL) in vials. A previously validated electro-spray tandem mass spectrometry method developed for the determination of succinylcholine dichloride in plasma was used. This method was based upon a stable isotope dilution assay using hexadeuterosuccinylcholine diiodide as the internal standard and was shown to be specific, sensitive, and reproducible. Calibration curves were plots of the ratios of intensities of the major product ions in the collision-induced dissociation spectrum for known concentration ratios of succinylcholine dichloride and hexadeuterosuccinylcholine diiodide in solutions. The concentration of succinylcholine dichloride was shown to decline linearly. After 1, 3, and 6 months at room temperature, the vial contents retained approximately 98%, 95%, and 90% of their inital concentration, respectively. We suggest, therefore, that succinylcholine dichloride can be stored safely at room temperature under normal daylight for 6 months.