Abstract
Menaquinone-7 (MK-7), a multipotent vitamin K2, possesses a wide range of biological activities, a precise curative effect, and excellent safety. A simple and rapid LC-APCI-MS/MS method for the determination of MK-7 in human plasma with single liquid-liquid extraction (LLE) extraction and 4.5-minute analysis time has been developed and validated. 4% Bovine Serum Albumin (BSA) was used as surrogate matrix for standard curves and endogenous baseline subtraction. This method was reproducible, reliable and was used to analyze of MK-7 in human plasma. The endogenous circadian rhythm and bioavailability of MK-7 were investigated in two randomized single-dose, open, one-way clinical trials (Study I and Study II). A total of five healthy male subjects were enrolled in Study I and twelve healthy male subjects in Study II. Single-dose (1 mg) of MK-7 was given to each subject under fasting condition, and all eligible subjects were given a restricting VK2 diet for four days prior to drug administration and during the trial. The experiment results of Study I demonstrated that endogenous MK-7 has no circadian rhythm in individuals. Both studies showed MK-7 are absorbed with peak plasma concentrations at ∼6 hours after intake and has a very long half-life time.
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