[Peculiarities of hypnotic effect and pharmacokinetics of hemisuccinate 3-hydroxyphenazepam (levana)].

The pharmacodynamics and pharmacokinetics of hemisuccinate 3-hydroxyphenazepam (HS-3-HPh, levana)--a new hypnotic 1,4-benzodiazepine derivative--have been studied. It is established that HS-3-HPh in doses of 0.05, 0.1 and 2 mg/kg produces reliable hypnotic action (shortens the period of falling asleep, reduces the number of awakenings at night-time, and increases sleep duration) in the hexenal sleep potentiation test on mice. After a 7-day drug administration, no withdrawal syndrome has been observed. The concentration of 3-oxyphenazepam (3-OP, the main metabolite of HS-3-HPh) in brain after drug administration is significantly higher than the content of 3-OP upon its introduction. The content of 3-OP upon its introduction rapidly decreases, while that upon the administration of HS-3-HPh is retained on a stationary level for a rather long time (about 6 h). It can be suggested that a specific character of HS-3-HPh hypnotic action is determined by peculiarities of its pharmacokinetics, namely, easier entering the brain and subsequent hydrolysis with release of the active metabolite (3-OP).