MIDD0301 (GL-II-93) sodium is an orally active inhibitor of γ-aminobutyric acid type A receptors (GABAAR) and an anti-asthmatic agent. It shows bio- and immunotoxicological safety in mice without affecting circulating lymphocyte, monocyte, and granulocyte counts. MIDD0301 sodium demonstrates no significant adverse immune responses under repeated dosing and is more favorable than Prednisone. It relaxes histamine-contracted tracheal smooth muscle in guinea pigs and humans, making it a valuable candidate for research in bronchoconstriction-related diseases.