D-685, a prodrug of D-520, demonstrates enhanced anti-Parkinsonian efficacy in a reserpinized Parkinson's disease (PD) animal model compared to its parent compound D-520. It effectively reduces the buildup of human α-synuclein (α-syn) protein and readily penetrates the brain [1].

D-685 (12 mg/kg; intraperitoneal injection daily; for one month) reduced α-synuclein accumulation in transgenic mice [1]. Compared to Lisuride alone, D-685 (10 μmol/kg; intraperitoneal injection) effectively reversed motor deficits and enhanced locomotor activity in male and female Sprague-Dawley rats (weighing 220-225 g) over a 6-hour period [1]. D-685 exhibited a high brain-to-plasma ratio (B/P: 4), indicating efficient brain penetration following intraperitoneal administration [1].