Emoxypine (ethylmethylhydroxypyridine) succinate (MEXIDOL®) is a 3-hydroxypyridine derivative which is quite similar in structure to Vitamin B6 (pyridoxine). The most important components of the mechanism of action of Mexidol® are its antioxidant and membranotropic effects, the ability to modulate functioning of receptors and membrane-bound enzymes, restore a neurotransmitter balance. Due to its mechanism of action Mexidol® has a wide range of pharmacological effects, realized on at least two levels – neuronal and vascular. It has antihypoxic, anti-ischemic, neuroprotective, nootropic, vegetotrophic, anti-stress, anxiolytic, anticonvulsant, anti-alcohol, cardioprotective, anti-atherogenic, geroprotective and other actions. Under the action of Mexidol®, it is observed an improvement in cerebral circulation and microcirculation. Emoxypine is distributed in Russia but it is widely unknown in other regions.

WAY-100635 is an achiral phenylpiperazine derivative that originally discovered as an antagotist of 5-HT1A receptor. Later WAY-100635 was described as a potent dopamine D4 receptor agonist. WAY-100635 was in preclinical studies for the treatment of Diabetes mellitus, Anxiety and Cognition disorders, howevere the development was discontinued. Isotope labeled WAY-100635 could be used for the study of central 5-HT 1A receptors with potential for application to the study of neuropsychiatric disorders and to the human pharmacology of psychoactive drugs.