TITLE:
Cerebral Bioavailability of Silexan—A Quantitative EEG Study in Healthy Volunteers
AUTHORS:
Wilfried Dimpfel, Winfried Wedekind, Angelika Dienel
KEYWORDS:
Silexan, Clinical Trial, Cerebral Bioavailability, qEEG, CATEEM
JOURNAL NAME:
Open Journal of Psychiatry,
Vol.5 No.3,
June
10,
2015
ABSTRACT: Background: A quantitative
EEG (qEEG) study was performed to investigate the cerebral bioavailability of
Silexan. Method: Twenty-four male and female healthy volunteers between 20 and
62 years of age were eligible for participation and received 160 or 80 mg/day
Silexan or placebo in randomised order according to a 3-way crossover design.
Treatment phases of 14 days were separated by 14-day washout periods. qEEG
recordings in conditions “eyes open”, “eyes closed”, as well as during
performance of 3 different cognitive tasks, were performed at 0, 1, 2, 3, and 4
h after drug administration on the first (single-dose assessment) and last day
of each treatment period (repetitive dose assessment). Result: Compared with
placebo, qEEG analysis revealed a significant increase of spectral power within
two hours in the alpha1 range (7.0 - 9.5 Hz), particularly in the
fronto-temporal region, where it was more pronounced after administration of
Silexan 160 mg/day than after the 80 mg/day dose. Changes in other frequency
bands were mainly attributable to circadian rhythm. No EEG changes typically
seen during the investigation of sedative drugs (general theta increase) were
observed. Cognitive task performance under both doses of Silexan was not
inferior compared with that in the placebo period. Conclusions: The study
provides evidence that ingredients of the anxiolytic lavender oil preparation
Silexan penetrate the blood-brain barrier and induce functional changes in the
CNS. The types of changes observed in the qEEG are consistent with the
anxiolytic clinical effect of the drug represented by increases of alpha1
spectral power. No sedative effects were observed. Silexan was well tolerated
during repetitive administration of doses up to twice the marketed dose.