Principal component analysis of production batches of the Ginkgo biloba extract EGb 761® over a period of 10 years on the basis of routine quality control parameters

Quality control of herbal extracts as drug substances in medicinal products requires the application of a battery of analytical parameters to guarantee safe use and reproducible therapeutic efficacy. In this respect, quality of EGb 761^® is regularly controlled by verification of the content of most important ingredients which contribute to efficacy (e.g. terpene lactones, flavone glycosides) and compliance with limits of unwanted compounds (e.g. ginkgolic acids). Additionally, general parameters like ash, color and particle size are analyzed (altogether 18 parameters).

Principal component analysis is a helpful tool to structure and illustrate large sets of data by converting numerous statistical variables in a reduced number of combinations. The calculated scores (principal components) represent the main variations or deviations of the data. Illustration through projection into 2D or 3D-representations is an easily interpretable way to confirm group specific properties.

The full set of routine quality control parameters of 379 production batches from the last ten years as well as data determined for 10 quantified extracts from other manufacturers were imported into SIMCA 14 and analyzed with univariate scaling for principal components (Fig. 1). Applying Hotelling's T2 statistic 99% of the Schwabe extracts (spheres) clustered within the 95% confidence interval, whereas all analyzed extracts from third party origin were outside this area (triangles).

The data demonstrate an exceptionally high consistency of extract composition over an extended period of time as basis for reproducible pharmacological activity, therapeutic efficacy and tolerability of EGb 761^®.

Fig. 1: Score scatter plot of Ginkgo extracts