The absorption features of glycyrrhizic acid in the drug formulation Phosphogliv

Abstract

Glycyrrhizic acid (GL), one of the active components of the Russian drug formulation Phosphogliv, is characterized by extremely low bioavailability. Absorption characteristics of GL after peroral administration of “Phosphogliv“ and GL sodium salt have been investigated using a sensitive method developed for GL determination in blood by means of high performance liquid chromatography coupled with mass-spectrometry (LC-MS). 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 the target ions of m/z 821.3 and 469.3 for GL and IS, respectively. The calibration curve was linear over the range of concentrations 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 GL as the component of the Phosphogliv drug formulation and solution of GL sodium salt during the first two hours after their single peroral administration to rats at the dose of 8.5 mg/kg. It was shown that GL absorption occurred within several minutes after peroral administration. Moreover, GL bioavailability after Phosphogliv administration was higher than after administration of GL sodium salt. This difference may be attributed to GL incorporation of the phospholipid nanoparticles structure.