Determination and pharmacokinetics of S-adenosylmethionine in human plasma by solid-phase extraction - LC-MS

Aim: To establish a rapid and sensitive solid-pbase extraction - LC-MS method for the analysis of S-adenosylinethionine (SAMe) in human plasma and study its pharmacokinetics on Chinese healthy volunteers after single oral administration. Methods: Using aciclovir as the internal standard (IS), the sample preparation involved solid-phase extraction after being deproteinized by perchloric acid. After the clean-up, samples were injected onto a Phenomenex Synerigi™ Hydro-RP C¹⁸ column (150 mm × 2.0 mm, 4 μm). The mobile phase consisted of 1% acetic acid and methanol and ran at a flow rate of 0.2 mL/min. A monopole mass spectrometer with an electrospray interface was operated in the selected-ion monitoring mode to detect the[M]⁺ ion at 399.2 m/z for SAMe and[M + H]⁺ ion at 226. 2 m/z for the internal standard. Results: The assay method was validated and linear calibration was demonstrated in the concentration range of 0.05-5 μ/mL for SAMe with the LOD of 0.05 μg/mL. Pharmacokinetic parameters were measured in 10 healthy Chinese volunteers who receiving a single dosage at 1000 mg of SAMe enteric-coated tablets. Conclusion: A sensitive and specific method for quantifying SAMe in human plasma has been developed and successfully applied to the clinical pharmacokinetic study of S-adenosylmethionine.