Development of UPLC–MS/MS method for quantitative analysis of curcumin in human plasma

A specific, very rapid, and sensitive ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method for quantitative analysis of curcumin in human plasma has been developed and validated. Diazepam was used as internal standard (IS). The analytes were isolated using liquid–liquid extraction method with the mixture of ethyl acetate–methanol (95:5). The organic solvents were evaporated, reconstituted in mobile phase, and injected to UPLC completed with UPLC BEH C18 column 1.7 μm, 2.1 × 100 mm Acquity® Waters as stationary phase, mixture of 0.15% formic acid–acetonitril (50:50, v/v) as mobile phase, and flow rate of 0.5 mL/min and detected in positive ionization mode tandem mass spectrometer operated in multiple reaction monitoring (MRM). The MS/MS ion transitions monitored were m/z 369.05 → 176.95 and 284.95 → 193 for curcumin and IS, respectively. The retention times for curcumin and IS were 1.7 and 1.4 min, respectively, and the linearity range was 1–100 ng/mL with a coefficient correlation (r) of 0.999 and lower limit of quantitation (LLOQ) of 1 ng/mL. The relative standard deviation (RSD) values of the intra- and inter-assay precisions of the method were below 8.3% and 12.7%, respectively, while the accuracy ranged from 89.5 to 98.7% and the extraction recovery of curcumin and IS was up to 86.6%. The data presented show that the method provides specific, very rapid, sensitive, precise, and accurate measurements of curcumin concentrations in human plasma.