Phosphodiesterase-5 inhibitors are therapeutically beneficial for the treatment of conditions where endothelial dysfunction plays a role in the underlying pathology. Although FDA approved PDE5 inhibitors demonstrate modest efficacy for the treatment of cardiovascular ailments such as PAH, these pharmaceutical agents are typically administered TID and may be associated with adverse events. Surface Logix has developed a novel PDE-5 inhibitor, SLx-2101, using the Pharmacomer� Technology Platform to drive small molecule drug design. This proprietary technology, based upon research pioneered by Professor George Whitesides, uses self-assembled monolayers (SAMs) to model small molecule-protein interactions and interfacial properties that determine PK and PD parameters. Utilization of the Pharmacomer� Platform allowed Surface Logix to specifically modify both the tissue distribution and the half life of a well-known short acting PDE pharmacaphore to deliver a drug that preferentially circulates into cardiovascular tissue to induce dose-responsive reduction of systolic blood pressure and heart rate in spontaneously hypertensive rats