Comparison of dried matrix spots and fabric phase sorptive extraction methods for quantification of highly potent analgesic activity agent (2R,4aR,7R,8aR)-4,7-dimethyl-2-(thiophen-2-yl)octahydro-2H-chromen-4-ol in rat whole blood and plasma using LC-MS/MS.

The methods for quantification of highly potent analgesic agent (2R,4aR,7R,8aR)-4,7-dimethyl-2-(thiophen-2-yl)octahydro-2H-chromen-4-ol in rat whole blood and plasma were developed and validated using dried matrix spots (DMS) or fabric phase sorptive extraction (FPSE) techniques in combination with LC-MS/MS. 2-Adamantylamine hydrochloride was used as an internal standard (IS). Chromatographic separation was carried out on a reversed-phase column (2.0×75 mm, 5 μm) using water containing 0.1% formic acid and methanol containing 0.1% formic acid as mobile phases in gradient mode at a flow rate of 200 μL/min. The mass spectrometric detection was performed using electrospray ionization (ESI) in positive ion mode. MRM transitions were m/z 284.5 → 137.2/157.4 for the analgesic agent and m/z 152.3 → 93.1/107.2 for IS. Calibration curves were linear within 20-5000 ng/mL in dried plasma spots (DPS) or dried blood spots (DBS) experiments. The linearity was obtained in the range of 20-5000 ng/mL and 50-5000 ng/mL for plasma-FPSE and blood-FPSE experiments, respectively. The intra- and inter-day accuracy and precision did not exceed acceptable limits. The mean extraction recovery (%) was 26 for DPS, 25 for DBS, 38 for plasma-FPSE, 31 for blood-FPSE.