Metabolism Elimination

The half-life of the flavonol glycosides administered as the product LI 1370 is 2-4 hours (19). Similar results wereobtained using 80 mg of the product EGb 761; half-lives of ginkgolides A and B were 4 and 6 hours, respectively. The half-life of bilobalide was 3 hours after administration of 120 mg of this extract. Similar results were reported in another study (52) using this same product; mean half-lives of ginkgolide A, ginkgolide B, and bilobalide were 4.5, 10.57, and 3.21 hours, respectively.

A study in rats using radiolabeled EGb 761 revealed a half-life of 4.5 hours, with elimination following first-order (linear) kinetics (19).

Approximately 70% of ginkgolide A, 50% of ginkgolide B, and 30% of bilobalide is excreted unchanged in the urine (19). Metabolites isolated from human urine after administration of EGb include a 4-hydroxybenzoic acid conjugate, 4-hydroxyhippuric acid, 3-methoxy-4-hydroxyhippuric acid, 3,4-dihydroxybenzoic acid, 4-hydroxybenzoic acid, hippuric acid, and 3-methoxy-4-hydroxybenzoic acid (vanillic acid) (53). In accord with previous data, these metabolites accounted for less than 30% of the administered EGb dose. Metabolites were not detectable in blood samples.

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