MIDD0301 is a potent positive allosteric α5β3γ selective GABAA receptor (GABAAR) ligand with EC50 of 17 nM.

MIDD0301 did not reveal signs of general toxicity as determined by animal weight, organ weight or haematology after employing oral administration of mice twice daily with 100 mg/kg MIDD0301 mixed in peanut butter for 28 days [1]. Spleen and thymus weights were unchanged and the number of small intestine Peyer's patches was not affected in MIDD0301-treated mice.MIDD0301 treatment did not alter IgG antibody responses to dinitrophenyl following dinitrophenyl-keyhole limpet haemocyanin immunization [1]. MIDD0301 relaxed histamine-contracted guinea pig ( P < 0.05, n = 6-9) and human ( P < 0.05, n = 6-10) tracheal smooth muscle ex vivo in organ bath experiments, dilates mouse peripheral airways ex vivo in precision-cut lung-slice experiments ( P < 0.001, n = 16 airways from three mice), and alleviates bronchoconstriction in vivo in mice, as assessed by the forced-oscillation technique ( P < 0.05, n = 6 mice) [2].