Comparative Quality Analysis of Three Marketed Melatonin Containing Products in Spain for the Improvement of Sleep

Background: Exogenous melatonin may effectively improve the sleep-wake cycle and sleep quality in subjects with age or disease related decrease in endogenous melatonin production or response. A controlled release melatonin-based medication, Circadin® has been developed and licensed for insomnia; in addition to several food supplements available on the market. However, the quality and release profile of these melatonin containing products may vary.

Aims: The current study aimed to compare three melatonin containing products, all of them marketed in Spain: a licensed medicine prolonged release tablet, Circadin® 2 mg, and two food supplements, Aquilea® 1,95mg and Oniria® 1,98 mg.

Materials and Methods: Three batches of each product were analyzed for melatonin content, inter-batch variability and dissolution profile.

Results: Our results confirm a large gap in quality control of the two melatonin containing food supplements, where Aquilea® and Oniria® showed poorer quality control as demonstrated by high variability between batches in melatonin content compared to Circadin®. Moreover, the extended release characteristics of Circadin® were evident in its profile, which exhibited an initial release of 70% at the 4-hour mark, followed by a consistent and sustained release lasting up to 8 hours.

Conclusion: In terms of the dissolution profile, only Circadin® provides the prolonged release profile as indicated in the specifications, with proven efficacy and safety for the improvement of sleep-onset, sleep maintenance and quality throughout the whole night.