Determination of morphine and oxymorphone in exhaled breath condensate samples: Application of microwave enhanced three-component deep eutectic solvent-based air-assisted liquid-liquid microextraction and derivatization prior to gas chromatography-mass spectrometry.

In this work, a microwave-enhanced air-assisted liquid-liquid microextraction method combined with gas chromatography-mass spectrometry has been developed for morphine and oxymorphone assessment in EBC samples. For this purpose, choline chloride-menthol-phenylacetic acid deep eutectic solvent (as an extraction solvent), butyl chloroformate (as a derivatization agent), and picoline (as a catalyst) are used. After performing predetermined extraction cycles in the microextraction method, the obtained cloudy solution is exposed to microwave irradiations to enhance extraction and derivatization efficiencies. The method provided low limits of detection (morphine 2.1 and oxymorphone 1.5 ng mL-1) and quantification (morphine 7.2 and oxymorphone 5.2 ng mL-1) in the EBC samples. The method had proper repeatability, accuracy, and stability expressed as relative standard deviations less than 5.1, 9, and 9%, respectively. The developed method was successfully used to determine morphine and oxymorphone concentrations in the EBC samples of addict patients.

Simultaneous determination of oxymorphone and its active metabolite 6-OH-oxymorphone in human plasma by high performance liquid chromatography-tandem mass spectrometry.

A selective high performance liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the simultaneous determination of oxymorphone and its active metabolite 6-OH-oxymorphone in human plasma was developed and validated using oxymorphone-d(3) as the internal standard. Chromatographic conditions were optimized to separate oxymorphone from the other metabolite, oxymorphone-3-glucuronide, which may convert to oxymorphone in MS ion source, resulting in inaccurate quantitation of oxymorphone. Solid phase extraction (SPE) was used to extract oxymorphone and 6-OH-oxymorphone from plasma. SPE offered the advantage of being able to remove the unwanted metabolite, oxymorphone-3-glucuronide, through the wash step during the extraction. The developed method was precise and reproducible as shown by good linearity of calibration curves (correlation coefficients ≥0.9968 for oxymorphone and ≥0.9967 for 6-OH-oxymorphone) with high intraday assay and interday assay precision (CV% ≤11.0% for oxymorphone and ≤12.6% for 6-OH-oxymorphone) over a range of 35/25 - 5000/5000 pg/mL for oxymorphone/6-OH-oxymorphone. The method has been successfully applied to analyze oxymorphone and 6-OH-oxymorphone in plasma from 19 healthy volunteers in a bioequivalence study. A total of 1026 samples were analyzed. Good linearity (average correlation coefficient 0.9988 for oxymorphone and 0.9966 for 6-OH-oxymorphone) was achieved with calibration curves and high precision (CV% ≤5.9% for oxymorphone and ≤10.9% for 6-OH-oxymorphone) was obtained with QCs.