Stability of sufentanil in human plasma samples

The stability of sufentanil in human plasma kept under various storage cond itions was investigated. Extraction was performed using solid phase extract ion with new mixed-mode cation exchange Oasis(R) MCX columns; quantificatio n was carried out using gaas chromatography equipped with a mass spectromet ry detector. When plasma was left at 4 degreesC in nonsilanized tubes, conc entrations of sufentanil decreased significantly during the first hour. In plasma samples kept at -25 degreesC for 8 hours in nonsilanized glass tubes , a significant decrease of sufentanil concentrations was found, with an av erage loss of 10.1% of the initial concentration. A significant decrease oc curred when plasma was kept in silanized glass tubes for 12 hours at -25 de greesC. The current study emphasizes the importance of sampling and storage conditions for an accurate determination of sufentanil concentration in pl asma.