PURPOSE: To actively separate a residual organic solvent and to recover the subject high-quality drugs with a small amount of residues without damaging qualities by bringing glycyrrhizic acid, a salt thereof, etc., into contact with a carbon dioxide gas in a supercritical state.
CONSTITUTION: Glycyrrhizic acid, a salt thereof, etc., is brought into contact with a carbon dioxide gas in a supercritical state to extract and separate a residual organic solvent. In the extraction, the extraction and separation are carried out under 50kg/cm2 to 500kg/cm2 extraction pressure, at critical/ extraction temperature of no lower than 80°C, under atmospheric/separation pressure of no lower than 60kg/cm2 and at critical/separation temperature of no lower than 60°C. Further when glycyrrhizic acid, a salt thereof, etc., is previously humidified into a proper water content and the residual organic solvent is extracted, advantageously the action of carbon dioxide gas is more activated and extraction time can be shortened.
MORIKAWA KATSUMI
MATSUYA TOSHIHIKO
ONAKA SETSUO
NAKANISHI YOSHIHIRO
