Determination of propofol glucuronide from hair sample by using mixed mode anion exchange cartridge and liquid chromatography tandem mass spectrometry

Quantitation of propofol metabolites by LC-MS/MS demonstrating long detection window for urine drug monitoring

Introduction

Chromatographic methods for analysis of propofol and its metabolites have been widely used in pharmacokinetic studies of propofol distribution, metabolism, and clearance. Application of chromatographic methods is also needed in clinical and forensic laboratories for detecting and monitoring propofol misuse.

Objective

We report a method for sensitive analysis of propofol, propofol 1-glucuronide (PG), 4-hydroxypropofol 1-glucuronide (1-QG), 4-hydroxypropofol 4-glucuronide (4-QG) and 4-hydroxypropofol 4-sulfate (4-QS) in urine by LC-MS/MS analysis. The method employs a simple dilute-and-analyze sample preparation with stable isotope internal standardization.

Results

Validation studies demonstrate a linear calibration model (100-10,000 ng/mL), with dilution integrity verified for the extended range of concentrations experienced in propofol use. Criteria-based validation was achieved, including an average coefficient of variation of 6.5 % and a percent bias of -4.2 ng/mL. The method was evaluated in 12 surgical patients, with monitoring periods lasting up to 30 days following intravenous propofol administrations of 100-3000 mg on the day of surgery. While the concentration ratio of PG to 4-hydroxy propofol metabolite decreased significantly in the days following surgery, PG maintained the highest concentration in all specimens. Both PG and 1-QG were detectable throughout the monitoring periods, including in a patient monitored for 30 days. Lower concentrations were determined for 4-QG and 4-QS, with evidence of detection up to 20 days. Propofol was not detectable in any urine specimens, thereby proving ineffective for identifying drug use.

Conclusion

The validated method for quantifying propofol metabolites demonstrates its applicability for the sensitive detection of propofol misuse over a long window of drug-use detection.

First derivative synchronous spectrofluorimetric method for the simultaneous determination of propofol and cisatracurium besylate in biological fluids

Propofol and cisatracurium besylate have been simultaneously determined using a highly sensitive first derivative synchronous spectrofluorometric method. The method is based on measuring first derivative synchronous spectrofluorimetric amplitude at Δλ = 40 nm with a scanning rate of 600 nm/min. The different experimental parameters affecting the fluorescence intensity of the two drugs were carefully studied and optimized. The amplitude-concentration plots were rectilinear over the range 40.0-400.0 ng/mL and 20.0-280.0 ng/mL for propofol and cisatracurium, respectively with lower detection limits of 4.0 and 2.35 ng/mL and quantification limits of 12.1 and 7.1 ng/mL for propofol and cisatracurium, respectively. The proposed method was successfully applied for the determination of the two compounds in synthetic mixtures and in commercial ampoules. The high sensitivity attained using the proposed method allowed the simultaneous determination of both drugs in spiked plasma samples. The mean % recoveries in spiked human plasma (n = 3) were 96.53 ± 0.90 and 96.20 ± 1.64 for each of propofol and cisatracurium, respectively. The method was validated in compliance with International Council of Harmonization (ICH) Guidelines.

Simultaneous HPLC Determination of Cisatracurium and Propofol in Human Plasma via Fluorometric Detection

The proposed method describes a high performance liquid chromatographic method with fluoremetric detection for the determination of cisatracurium (CIS) and propofol (PRP) simultaneously, which are co-administered as a pre-operative injection mixture. The separation of the two drugs was achieved using monolithic column (100 mm and 4.6 mm internal diameter) and mixture of methanol and 0.1 M phosphate buffer in the ratio of 80:20 (v/v) at pH 4.5 as a mobile phase. The fluorescence detection was carried out at 230/324 nm. The procedure showed good linearity through the concentration ranges of 0.01-1.00 μg/mL and 0.1-3.0 μg/mL with limits of detection of 0.002, 0.030 μg/mL and limits of quantification of 0.006, 0.100 μg/mL for CIS and PRP, respectively. Simultaneous determination of CIS and PRP in spiked human plasma samples was additionally executed and the results were satisfactory precise and accurate.