Advanced pharmacological and pharmacokinetic evaluation of 1,3 dimethylpurine-2,6-dione derivative (GR-14) with prominent mood-modulating activity in rats.

Background: Research on new candidates for antidepressant/anxiolytic drugs from the long-chain arylpiperazines (LCAPs) group containing a 1,3-dimethylpurine-2,6-dione as a terminal amide fragment fits into the modern exploration trend. This study aimed to examine, for the first time in male Wistar rats, pharmacodynamic (antidepressant- and anxiolytic-like) and pharmacokinetic properties of 7-(5-(4-(3-chlorophenyl)piperazin-1-yl)pentyl)-1,3-dimethyl-3,7-dihydro-1 H-purine-2,6-dione hydrochloride (GR-14).

Methods: Antidepressant- and anxiolytic-like activities have been assessed in the forced swim test (FST) and Vogel conflict drinking test, respectively. The pharmacokinetic characteristics of GR-14, its distribution into rat tissues, and several in vitro ADME-Tox parameters (hepatocytotoxic, neurocytotoxic, metabolic stability) have been defined.

Results: GR-14 produces strong and dose-dependent antidepressant- and anxiolytic-like effects in both tests used. Pharmacokinetic findings demonstrate that GR-14 reveals linear pharmacokinetics tested after intravenous (iv) and was rapidly absorbed after oral (po) administration. It rapidly crosses the blood-brain barrier (BBB) which is vital for therapeutic effects in vivo in psychiatric diseases, depression, and anxiety. Moreover, it is slowly eliminated from the brain, maintaining concentrations higher than those in plasma at the last time point measured. Further studies have also shown that GR-14 is an average high-clearance drug in rat liver microsomes and exerts neither hepatocytotoxic nor neurocytotoxic effects in vitro.

Conclusion: The tested derivative GR-14 presents prominent mood-modulating activity in rats and has promising pharmacokinetic parameters and a good safety profile. The beneficial pharmacology and pharmacokinetics of GR-14 in vivo are in high concordance with its profile in vitro, thus underlining very hopeful properties to support the early development process.