Myricetin is a widely distributed bioactive flavonoid with scientific interest attributed to its anti-oxidant, antitumor, and anti-inflammatory properties. A specific and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed and validated for identification and quantification of myricetin in rat plasma after oral and intravenous administrations. Kaempferol was used as an internal standard. Followed by β-glucuronidase and sulfatase hydrolysis and liquid-liquid extraction with ethyl acetate, the analytes were separated on an Acquity UPLC BEH C18 column (2.1×50 mm, 1.7 μm) and analyzed in the selected ion recording with a negative electrospray ionization mode. The developed method was validated for selectivity, accuracy, precision, linearity, recovery, stability and matrix effect. The assay was validated over a wide concentration range of 2-4,000 ng/mL. Intra- and inter-day precisions were all less than 13.49% and accuracy ranged from 95.75 to 109.80%. The present method was successfully applied to investigate a pharmacokinetic study of myricetin following intravenous and oral administrations to rats. The absolute bioavailability was found to be 9.62% and 9.74% at 2 oral doses (50 mg/kg and 100 mg/kg, respectively), which indicated myricetin was poorly absorbed after oral administration. To our knowledge, this is the first pharmacokinetic evaluation of myricetin as a single active pharmaceutical ingredient in preclinical studies.

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Pharmacokinetic properties of isorhamnetin, quercetin, and kaempferol in three different total flavones of Hippophae rhamnoides (TFH) preparations were compared after oral administration to beagle dogs by a UPLC-MS method. The pharmacokinetic results showed that C max of isorhamnetin and quercetin in TFH solid dispersion (TFH-SD) and TFH self-emulsifying (TFH-SE) preparations was significantly enhanced than that in TFH preparations (p < 0.05). The AUCs of isorhamnetin and quercetin in TFH-SD were 5.9- and 3.1-fold higher than that of TFH, while the AUCs of isorhamnetin and quercetin in TFH-SE were 3.4- and 2.4-fold higher than that of TFH. These findings suggested that the oral bioavailability of isorhamnetin and quercetin in beagle dogs can be significantly increased in TFH-SD and TFH-SE preparations compared to TFH preparations, which was helpful to explore the new forms for oral administration TFH and explain their in vivo processes.