Determination of fentanyl in sweat and hair of a patient using transdermal patches.

Fentanyl is a synthetic opioid used to treat intense chronic pain. In this study, the authors report detection and quantification of fentanyl in sweat and hair of a patient receiving fentanyl (25 microg/h) via a transdermal therapeutic system (TTS) for 22 days. Sweat was collected using sweat patches every night on days 13-21 of the therapy, and hair was collected 12 weeks after the end of the treatment. Detection and quantification was performed with liquid chromatography-tandem mass spectrometry using electron spray ionization in selected reaction monitoring mode. Alfentanyl was used as internal standard for quantification in hair and in sweat. Sodium ions have been used as endogenous internal reference for determination of volume of sweat excreted on each patch. Results show presence of fentanyl in both matrices. Fentanyl concentrations in sweat varied from 0.17 to 1.02 ng/microL, and time-resolved segmented hair analysis showed a maximum fentanyl concentration of 0.48 ng/mg of hair during the period of the therapy.

Quantification of lorazepam and lormetazepam in human breast milk using GC-MS in the negative chemical ionization mode.

Lormetazepam (Loramet is a benzodiazepine mainly used as an hypnotic to treat insomnia. Lorazepam (Temesta) is used as an anxiolytic, tranquilizer, sedative, and anticonvulsant, and it is the major metabolite of lormetazepam. In this study, we designed a method to simultaneously detect and quantify these substances in human breast milk. Solid-phase extraction of 2 mL of milk was followed by derivatization with a trimethylsilyl reagent. Separation and detection was performed using gas chromatography coupled to mass spectrometry in the negative chemical ionization mode. Calibration curves were linear in the ranges of 10-200 and 1-20 ng/mL for lorazepam and lormetazepam, respectively. Limits of detection were estimated at 0.016 ng/mL for lormetazepam and 0.100 ng/mL for lorazepam. Our method was applied to real case samples from a woman receiving both benzodiazepines. Lorazepam concentrations varied from 55.3 to 123.1 ng/mL, and lormetazepam concentrations varied from 1.7 to 7.3 ng/mL.

Determination of nevirapine and efavirenz in plasma using GC/MS in selected ion monitoring mode.

An accurate, selective, and sensitive method for the determination of the nonnucleoside reverse transcriptase inhibitors (NNRTIs) nevirapine (nvp) and efavirenz (efv) in human plasma using gas chromatography-mass spectroscopy in selected ion monitoring mode (GC/MS-SIM) was developed. Solid-phase extraction (SPE) gave extraction yields near 100% for both nvp and efv, and calibration curves were linear over the therapeutic concentration ranges. Variation of intraday and interday precision was below 5%. Intraday and interday inaccuracies varied between 0.6% and 10.4%. The lower limits of detection using a 200-microL plasma sample were 27 ng/mL for nvp and 26 ng/mL for efv, and the lower limits of quantification were 54 ng/mL and 72 ng/mL, respectively. The method was applied to the determination of nvp and efv in plasma specimens of 73 patients in HIV stage III or IV and on antiretroviral treatment in Kigali, Rwanda.