OBJECTIVETo investigate the effect of temperature on the partition coefficient of isoflurane and sevoflurane in perflurocarbonate emulsion (Oxygent(TM)).

METHODSThe partition coefficients of isoflurane and sevoflurane in perflurocarbonate emulsion (Oxygent(TM)) were measured at different temperatures (4, 22, 27, 32 and 37 degrees celsius;) using syringe-flask double headspace equilibration technique with gas chromatography, and the relationship between the partition coefficients and the temperature was analyzed.

RESULTSAt 4, 22, 27, 32 and 37 degrees celsius;, the partition coefficients of isoflurane in Oxygent(TM) were 85.30∓5.60, 40.48∓1.09, 37.14∓3.64, 27.38∓2.28 and 24.66∓1.03, and those of sevoflurane were 91.54∓5.40, 42.50∓0.91, 37.21∓2.76, 25.43∓1.03 and 28.05∓1.74, respectively. The partition coefficients of sevoflurane at 4, 22 and 37 degrees celsius; were significantly higher than those of isoflurane (P<0.05). The regression equations between the partition coefficient and temperature for isoflurane and sevoflurane were Y=-1.893X+89.20 (R(2)=0.942) and Y=-2.075X+95.58 (R(2)=0.951), respectively. An inverse linear relationship was found between temperature and the partition coefficient.

CONCLUSIONWithin a specified range of temperatures, the partition coefficients isoflurane and sevoflurane decrease as the temperature increases. Sevoflurane shows a high solubility in Oxygent(TM) as compared to isoflurane.