title: Determination of the conversion factor for silymarin - a solution for the problems associated with new assay methods in the pharmacopoeia.
abstract: In pharmacopoeial monographs for herbal drugs and herbal preparations, conventional assay methods such as colorimetry or spectophotometric assays are often replaced by modern, more specific and reliable methods, e.g. liquid chromatography (LC). However, existing dosage recommendations in the monographs on efficacy and safety of herbal medicinal products which are an important basis for licensing procedures do not refer to the mandatory new methods but to the existing photometric methods. The laboratory comparison of the determination of silymarin of Milk Thistle extract shows that a conversion factor can be calculated which allows a correlation between the new and the existing method. It is suggested that this factor should be included in the Ph. Eur. monograph on Milk Thistle extract, allowing reference to dosages given in official monographs (e.g. ESCOP, HMPC). The solution to use a conversion factor should also be applied to other herbal drugs and herbal preparations, especially for standardised extracts.
authors.affiliation: Finzelberg GmbH & Co KG, Kooperation Phytopharmaka GbR. Bonn, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Gaedcke
authors.forename: M
authors.initials: M
authors.lastname: Hubbert
authors.forename: H
authors.initials: H
authors.lastname: Kurth
authors.forename: F
authors.initials: F
authors.lastname: Lang
authors.forename: S
authors.initials: S
authors.lastname: Saar
authors.forename: B
authors.initials: B
authors.lastname: Steinhoff
authors.forename: M
authors.initials: M
authors.lastname: Tawab
authors.forename: H
authors.initials: H
authors.lastname: Vratzia
authors.forename: A
authors.initials: A
authors.lastname: Wixforth
mesh_terms: D000465:Algorithms; D000975:Antioxidants / Q000032:analysis*; D002853:Chromatography, Liquid; D007202:Indicators and Reagents; D020944:Silybum marianum / Q000737:chemistry; D010602:Pharmacopoeias as Topic; D010783:Photometry; D010936:Plant Extracts / Q000032:analysis; D012015:Reference Standards; D012838:Silymarin / Q000032:analysis*; D012996:Solutions
chemical_list: D000975:Antioxidants; D007202:Indicators and Reagents; D010936:Plant Extracts; D012838:Silymarin; D012996:Solutions