Semi-Empirical Study of the Drug Riociguat, an Important Drug for Oral Treatment against Chronic Thromboembolic Pulmonary Hypertension

The drug Riociguat is an orally administered medication, unique in the treatment of Chronic Thromboembolic Pulmonary Hypertension and still effective in common Pulmonary Hypertension. The aim of the present study was to use the semi-empirical method Parametrical Model 7 (QM-PM7) to perform an in silico characterization of the drug Riociguat using semi-empirical calculations based on quantum mechanics. The molecular structure of the anti-CTPH compound, Riociguat, was geometrically optimized, until its conformation was as stable as possible and the stationary minimum-energy minimum point (Self Consistent Field) was reached, reaching -51.14967 KJ mol-1 and its Heat of formation (-12.22507 KCAL mol-1). It can be observed that the best area for nucleophilic reactions is located in the nucleophilic sites, nitrogen and oxygen atoms, which is demonstrated by the GAP values that indicated several regions with high reactivity, As well as a high Gap value. These data generated during the production of this article, aim at a better understanding of the structure and the drug, which can serve as the basis for a later work of elaboration of more biologically efficient analogues, or for the realization of molecular docking studies with Riociguat.