グリチルリチン自己投与製剤開発に関する基礎的検討

抄録

The aim of this study was to develop glycyrrhizin (GZ) dosage forms which can be self administered, such as intranasal solutions and pen-type subcutaneous injections. We found that the use of L-arginine and L-histidine as pharmaceutical adjuvants helped inhibit gel formation by GZ, and the optimal formulation was a GZ solution (400 mg/mL) prepared using a 20 mM phosphate buffered solution (pH 7.4) containing 4% L-arginine and 4% L-histidine. The apparent phase behavior and GZ content of this GZ formulation did not change for at least 2 weeks when kept at 4°C and 60°C. After intranasal and subcutaneous administration (50 mg/kg) to rats, the bioavailability of glycyrrhizin was 17% and 77%, respectively. These results suggested that the subcutaneous administration of our highly concentrated GZ solution is a useful substitute for commercial GZ products that are administered intravenously.