LC-MS/MS determination of GTS-201, a dipeptide mimetic of the brain-derived neurotrophic factor, and neurotransmitter metabolites with application to a pharmacokinetic study in rats

Abstract

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family with diverse psychopharmacological effects including antidepressant and anxiolytic actions. However, the clinical use of BDNF is limited due to its poor pharmacokinetic properties. The development of low-molecular-weight BDNF mimetics passing through the blood-brain barrier is an emerging strategy for improved managing psychiatric diseases. The present study characterizes a novel dipeptide mimetic of the 2nd BDNF loop named GTS-201, which exhibits psychotropic properties in experimental animal models of anxiety and alcohol dependence. The aim of this work was to study the pharmacokinetics of GTS-201 in rats at a saturating dosage of 5 mg/kg applied by the intraperitoneal route and to characterize the effects on neurotransmitter levels in the blood and brain. The maximum concentration (Cmax) of GTS-201 in the plasma (867 ± 69 ng/ml) was recorded at 35 ± 7.7 min after administration (Tmax) with a half-elimination period (T1/2) of 19.5 ± 1.8 min, while in the brain tissue Cmax was 14.92 ± 3.11 ng/ml, Tmax was 40.0 ± 7.7 min and T1/2 were 87.5 ± 12.7 min. The relative tissue availability of the GTS-201 for the brain reached 2.9%. At the dose applied, GTS-201 induced a significant increase of serotonin (5-fold) and dopamine levels in the brain tissue (8-fold) along with a decrease in cortisol content in blood plasma 45 min after acute administration. In summary, GTS-201 crosses the blood-brain barrier after acute administration and affects the activity of serotonergic and dopaminergic systems, which may underlie its neuropsychotropic effects described previously.