Effect of exposure to fentanyl aerosol in mice on breathing pattern and respiratory variables.

The breathing pattern of mice that were exposed to fentanyl aerosol was studied (2.7, 5.7, 6.0, 10.0, and 23.6 microg/m(3); for 1 hour), using dimethyl sulfoxide as a vehicle. This study was conducted in a head-only exposure assembly. Body plethysmographs connected to a volumetric pressure transducer were used to capture the respiratory signals, and an on-line computer program capable of recognizing the changes in the breathing pattern was used for monitoring the respiratory pattern. The response of mice to fentanyl exposure was found to be concentration dependent. A lower concentration (2.7 microg/m(3)) showed fast recovery and no mortality, while 100% mortality was observed at a higher concentration (23.6 microg/m(3)). No sensory, pulmonary irritation, and airway limitation in mice was observed, and death occurred probably due to respiratory depression. The concentration that decreased 50% of the respiratory frequency (RD(50)) was estimated to be 6.4 microg/m(3). The extrapolated human threshold limit value, calculated from the RD(50) value, was found to be 0.192 microg/m(3). The concentration that caused 50% mortality in exposed mice (LC(50)) was estimated to be 8.8 microg/m(3). This study shows that aerosolized fentanyl does not cause sensory and pulmonary irritation, and since the RD(50) and LC(50) are very close with a low safety margin, this type of sedative should not be used as an incapacitating agent.

Gas chromatographic retention indices of fentanyl and analogues.

Narcotic analgesics of the fentanyl class are characterized by high potency and relatively short duration of action. These compounds nowadays have become a substitute for heroine and are highly addictive for abusers. Herein, we report retention indices of fentanyl and its eighteen analogues relative to the homologous n-alkane series. These values are determined on a moderately polar BP-5 capillary column under programmed temperature and isothermal chromatographic conditions. The analogues differ in the substituent attached to the piperidine ring nitrogen, and retention indices are found to vary according to the nature of the substituent. The effects of chromatographic conditions like temperature programming rate, carrier gas flow rate, and oven temperature are studied. Retention indices are also determined on a non-polar BP-1 column to study the influence of stationary phase polarity. Standard deviation of all the RI values is less than one index unit.

Use of single-drop microextraction for determination of fentanyl in water samples.

Fentanyl is a very potent synthetic narcotic analgesic. Because of its strong sedative properties, it has become an analogue of illicit drugs such as heroin. Its unambiguous detection and identification in environmental samples can be regarded as strong evidence of its illicit preparation. In this paper we report application of single-drop microextraction (SDME) for analysis of water samples spiked with fentanyl. Experimental conditions which affect the performance of SDME, for example the nature of the extracting solvent, sample stirring speed, extraction time, ionic strength, and solution pH, were optimized. The method was found to be linear in the concentration range 0.10-10 ng mL(-1). The limits of quantitation and detection of the method were 100 pg mL(-1) and <75 pg mL(-1), respectively. This technique is superior to other sample-preparation techniques because of the simple experimental set-up, short analysis time, high sensitivity, and minimum use of organic solvent.