Irsenontrine (E2027) maleate is a selective and orally active inhibitor of phosphodiesterase 9 (PDE9). It can be utilized in the study of neurological diseases.

Irsenontrine maleate, administered orally at doses of 0.3 and 3.3 mg/kg, significantly improves novel object exploration in scopolamine-induced rats at the higher dose [1]. Furthermore, a combined treatment of Irsenontrine maleate and memantine hydrochloride, each at 1 mg/kg orally, results in a significantly increased exploration of the novel object compared to treatment with memantine hydrochloride alone at the same dosage [1].