Melatonin can be used to treat sleep disorders, but it has poor bioavailability, and has a half-life in the body of only about 15 minutes
The body’s circadian rhythms – the normal variations in physiological parameters during the day – are very closely involved in regulation of sleep patterns. If these rhythms become out of synch, sleep patterns tend to be disrupted. Melatonin, a hormone produced in the pineal gland, is involved in the sleep–wake cycle of the circadian rhythm. It is excreted in response to a cascade of signals resulting from changes in light level, and the level that is present in the bloodstream varies through the day, with its release eventually resulting in the process of falling asleep.
Melatonin can be used to treat sleep disorders, but it has poor bioavailability, and has a half-life in the body of only about 15 minutes. In addition, side-effects can be an issue as it binds non-selectively to many different receptors within the brain. As a result, there has been a degree of interest in analogues, and one, Takeda’s ramelteon (Rozerem) is approved in the US. Another, tasimelteon, is being developed by Vanda Pharmaceuticals, under licence from Bristol-Myers Squibb.1 It acts as a selective agonist at the MT1 and MT2 melatonin receptors in the brain’s suprachiasmic nucleus, which is a group of neurons in the anterior hypothalamus.
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Tasimelteon
In a Phase II trial in induced insomnia, 39 healthy subjects were monitored for seven nights – three at baseline, three after a five-hour advance of the sleep-wake cycle with treatment with 10, 20, 50 or 100mg of tasimelteon or placebo before sleep, and a further night after treatment.2 The drug reduced sleep latency, and also increased sleep efficiency compared with placebo, with the shift in plasma melatonin rhythm being dose-dependent.
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http://www.manufacturingchemist.com/technical/article_page/Sleep_disorders__tasimelteon/90220
