Astragalus glycyphyllos: extraction condition optimisation, extract standardisation and solid dosage form preparation

Astragalus glycyphyllos is used in folk medicine as a diuretic, antispasmodic, antihypertensive and anti-inflammatory agent. A number of flavonoids and saponins have been identified in the species, which exhibit antioxidant, cytoprotective, neuroprotective, hepatoprotective and immunostimulating activity. This makes the species promising for use in medical practice. In the present study, the conditions for obtaining a dry extract from the aboveground part have been optimised in order to include it in appropriate dosage forms. Two extraction methods were used – Soxhlet apparatus and percolation. The influence of solvent type and temperature on the amount of active and ballast substances during extraction was studied. The liquid extracts were dried by lyophilisation and standardised by ultra-high-performance liquid chromatography–mass spectrometry (UHPLC-MS) with high resolution for triterpene saponins. A comprehensive technology for obtaining a dry extract from the aerial part of A. glycyphyllos , easily applicable under production conditions, as well as a method for quantitative determination of triterpene saponins, was proposed. The obtained standardised extract was successfully used for the preparation of hard gelatine capsules, which were technologically characterised. The results demonstrate the overall feasibility of obtaining a dosage form.