Abstract: Glycyrrhizic acid (GL) - one of the active components of the Russian drug formulation "Phosphogliv" possesses extremely low bioavailability. A sensitive method for GL determination in blood using high performance liquid chromatography coupled with mass-spectrometry (HPLC-MS) has been developed in order to investigate absorption characteristics of glycyrrhizic acid after peroral administration of "Phosphogliv" and GL sodium salt. Separation of blood components was achieved on the analytical reverse-phase column C18 "EcoNova" ProntoSIL, using a gradient mode. Detection of GL and an internal standard (IS) (glycyrrhetic acid) was performed using electrospray ionization with the selected ion monitoring in negative mode (SIM) using target ions at m/z 821.3 for GL and 469.3 for IS. The calibration curve was linear over the range of 50-5000 ng/ml (the correlation coefficient was 0.995). The detection limit for GL in blood was 25 ng/ml and the lower limit of quantification was 50 ng/ml.The developed method has been applied to compare absorption efficiency of glycyrrhizic acid as the component of "Phosphogliv" composition and solution of GL sodium salt during first two hours after their single peroral administration to rats at the dose of 8.5 mg/kg. It was shown that GL absorption occurs several minutes after peroral administration. Moreover, GL bioavailability after administration of drug "Phosphogliv" was higher than after administration of GL sodium salt. This difference may be attributed to incorporation of glycyrrhizic acid in the phospholipid nanoparticles structure.
Reference: Voskresenskaya A.A., Medvedeva N.V., Prozorovskiy V.N., Moskaleva N.E., Ipatova O.M., The absorption features of glycyrrhizic acid in composition of drug "phosphogliv", Biomeditsinskaya khimiya, 2012, vol: