Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1. Pharmacodynamic properties
Pharmacotherapeutic group: other anti-dementia drugs, peripheral vasodilatators ATC code: N06DX02, C04

The following pharmacological effects have been proven in animal experiments with the quantified extract EGb 761 contained in Cerebonin® 120 mg: Increase in tolerance to hypoxia, in particular of the cerebral tissue, inhibition of the development of traumatically or toxically induced brain edema and acceleration of its regression, reduction of retina edema and lesions of retina cells, inhibition of age-related reduction of muscarinergic choline receptors and alpha-2-adrenoceptors as well as promotion of choline uptake in the hippocampus, enhancement of memory performance and learning capacity, improved compensation of disturbances of equilibrium, circulatory increase in particular in the region of microcirculation, improvement of the rheological properties of the blood, inactivation of toxic oxygen radicals (flavonoids), PAF antagonism (ginkgolides) and neuroprotective effect (ginkgolides A and B, bilobalide).

Hypoxia-protective effects, increase of blood flow, in particular in the microcirculatory region and improvement of the rheological properties of the blood could be demonstrated in humans.

Pharmacokinetic Properties

5.2. Pharmacokinetic properties
Cerebral bioavailability of the quantified extract EGb 761 in humans was demonstrated in the pharmaco-EEG on the base of dose-dependent effects on cerebro-electrical activity.
After oral application of 80 mg Ginkgo extract, the terpene lactones ginkgolide A, ginkgolide B and bilobalide showed in humans a very good absolute bioavailability of 98% for ginkgolide A, 79% for ginkgolide B and 72% for bilobalide. Maximum plasma concentrations were 15 ng/ml for ginkgolide A, 4 ng/ml for ginkgolide B and approx. 12 ng/ml for bilobalide. Half-lives were 3.9 hours (ginkgolide A), 7 hours (ginkgolide B) and 3.2 hours (bilobalide).
Plasma-protein binding (human blood) is 43% for ginkgolide A, 47% for ginkgolide B and 67% for bilobalide. In the rat, a resorption rate of 60% was determined following oral ad- ministration of 14C radioactively tagged extract EGb 761. Maximum plasma concen- trations were measured 1.5 hours after administration; half-life was 4.5 hours. A second plasma peak 12 hours after administration is indicative of an enterohepatic shunt.