AIM To investigate physicochemical stability of sevoflurane in dimethyl sulfoxide using gas chromatography with a flame ionization detector and nuclear magnetic resonance(NMR).METHODS 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 ℃, 6 ℃, and-10 ℃) 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 ℃, 40 min), and by ~1H, ~(19) F, and proton-decoupled ~(19) F nuclear magnetic resonance.RESULTS 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 ℃, 4 ℃ and 25 ℃. The NMR spectra showed signals consistent with the sevoflurane structure in all the dilutions at-10 ℃, 4 ℃ and 25 ℃. In the ~1H spectrum, two signals corresponding to the sevoflurane molecule were observed at 5.12 and 4.16 parts per million(ppm5). In the ~(19)F-NMR spectrum, two signals were observed at-76.77 ppm and-157.13 ppm. In the ~(19)F NMR CPD, two signals were observed at-76.77 ppm and-157.13 ppm. The first one showed a doublet(JF-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(JF-F = 3.1 Hz).CONCLUSION 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. AIM To investigate physicochemical stability of sevoflurane in dimethyl sulfoxide using gas chromatography with a flame ionization detector and nuclear magnetic resonance (NMR) .METHODS 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 days. Sterile 1 mL polypropylene amber syringes to minimize light degradation, caps The presence of sevoflurane and its degradation products in the samples was determined by gas chromatography with flame ionization detector (260 ° C for 40 min), and by ~ 1H, ~ (19) F, and proton-decoupled ~ ( 19) F nuclear magnetic resonance. RESULTS The gas chromatography showed 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 sevofluran 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 (ppm5). In the ~ (19) F-NMR spectrum, both signals were observed at -76.77 ppm and -157.13 ppm. In the ~ (19) F NMR CPD, two signals were observed at -76.77 ppm and -157.13 ppm. The first one showed a doublet (JF-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 (JF-F = 3.1 Hz) .CONCLUSION 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.