Batch-to-Batch Reproducibility of St. John's Wort Preparations

Abstract

Over the last few years, St. John's Wort products have enjoyed a tremendous surge in interest and sales for the therapy of mild to moderate depression. Although the complete spectrum of active substances in this herbal extract has not yet been elucidated, it is certain that hyperforin is an important component. Further, it appears that the hypericins may also contribute to the antidepressive activity. In this study, the content uniformity of eleven St. John's Wort products sold exclusively in pharmacies was determined. The main objective was to determine the batch-to-batch reproducibility of the various products. The hyperforin was analysed according to a previously published HPLC method, while the total hypericin content was determined by an electrochemical method. The results indicate that some, but not all, products show very reproducible batch-to-batch properties. Also, individual products have different hypericin and hyperforin levels, and are therefore not switchable--even when products are manufactured under similar extraction and processing conditions, have the same raw material:extract ratios (on a dry basis) and contain the same amount of extract per unit dosage form.

Simultaneous determination of hypericin and hyperforin in human plasma with liquid chromatography–tandem mass spectrometry

“…Taking further into account that the concentrations of these two components in commercially available dry extracts are highly variable [14], an even lower limit of quantification (LOQ) of 0.5 ng/mL for hypericin and 0.05 ng/mL for hyperforin may be required for their quantification.…”

St. John’s Wort – an Overview

“…For many products sold outside pharmacies in Germany, the concentration and daily dosages of relevant constituents are far below those assumed to be necessary for relevant clinical effects [22]. Products only marketed by pharmacies in general have adequate quality but variations of composition occur from batch to batch [23].…”

St John’s wort extract (Ze 117) does not alter the pharmacokinetics of a low-dose oral contraceptive

“…These occurrences led regulatory authorities to take precautionary measures [8] and investigators to study interactions of St John's wort with other drugs and the possible mechanisms of these interactions. The St John's wort preparations on the market differ considerably in composition and dosage, which is the reason why study results are only valid for the product under investigation [9][10][11][12][13]. The extract Ze 117 used in this study is standardised to 0.2% hypericin and is characterised by its low content of hyperforin [10,14].…”

“…The St John's wort preparations on the market differ considerably in composition and dosage, which is the reason why study results are only valid for the product under investigation [9][10][11][12][13]. The extract Ze 117 used in this study is standardised to 0.2% hypericin and is characterised by its low content of hyperforin [10,14]. The recommended daily dosage is 500 mg, which is well documented to be clinically efficient in cases of mild to moderate depression [15][16][17].…”