To investigate physicochemical stability of sevoflurane in dimethyl sulfoxide using gas chromatography with a flame ionization detector and nuclear magnetic resonance (NMR).

Undiluted sevoflurane, plus dilutions 1:2, 1:5, 1:10, 1:25, and 1:50 in dimethyl sulfoxide were prepared in a vertical laminar flow cabinet class II type B and stored at different temperatures (23 °C, 6 °C, and -10 °C) for 45 d. Sterile 1 mL polypropylene amber syringes to minimize light degradation, caps and needles were used. The presence of sevoflurane and its degradation products in the samples was determined by gas chromatography with flame ionization detector (260 °C, 40 min), and by ¹H, ¹⁹F, and proton-decoupled ¹⁹F nuclear magnetic resonance.

The gas chromatography analysis showed sevoflurane and dimethyl sulfoxide (DMSO) retention times were 2.7 and 13.0 min, respectively. Pure DMSO injection into the column resulted in two additional peaks at 2.1 and 2.8 min. The same sevoflurane peak at 2.7 min was observed in all the dilutions at -10 °C, 4 °C and 25 °C. The NMR spectra showed signals consistent with the sevoflurane structure in all the dilutions at -10 °C, 4 °C and 25 °C. In the ¹H spectrum, two signals corresponding to the sevoflurane molecule were observed at 5.12 and 4.16 parts per million (ppm). In the ¹⁹F-NMR spectrum, two signals were observed at chemical shift -76.77 ppm and chemical shift -157.13 ppm. In the ¹⁹F{¹H}-NMR CPD, two signals were observed at chemical shift -76.77 ppm and chemical shift -157.13 ppm. The first one showed a doublet (J^F-F = 3.1 Hz) which integrated by six fluorine nuclei from the hexafluoro-isopropyl group. The second signal was integrated by a fluorine atom and showed a septuplet (J^F-F = 3.1 Hz).

This study shows that different concentrations of sevoflurane in dimethyl sulfoxide retain their chemical composition after exposure to different temperatures for a period of 45 d.

• Sevoflurane
• Dimethyl sulfoxide
• Nuclear Magnetic resonance
• Gas chromatography
• Skin ulcers
• Drug stability