Quality specifications for articles of botanical origin from the United States Pharmacopeia

Abstract

Background: In order to define appropriate quality of botanical dietary supplements, botanical drugs, and herbal medicines, the United States Pharmacopeia (USP) and the Herbal Medicines Compendium (HMC) contain science-based quality standards that include multiple interrelated tests to provide a full quality characterization for each article in terms of its identity, purity, and content.

Purpose: To provide a comprehensive description of the pharmacopeial tests and requirements for articles of botanical origin in the aforementioned compendia. Selective chromatographic procedures, such as high-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC), are used as Identification tests in pharmacopeial monographs to detect species substitution or other confounders. HPLC quantitative tests are typically used to determine the content of key constituents, i.e., the total or individual amount of plant secondary metabolites that are considered bioactive constituents or analytical marker compounds. Purity specifications are typically set to limit the content of contaminants such as toxic elements, pesticides, and fungal toxins. Additional requirements highlight the importance of naming, definition, use of reference materials, and packaging/storage conditions.

Methods: Technical requirements for each section of the monographs were illustrated with specific examples. Tests were performed on authentic samples using pharmacopeial reference standards. The chromatographic analytical procedures were validated to provide characteristic profiles for the identity and/or accurate determination of the content of quality markers.

Results: The multiple tests included in each monograph complement each other to provide an appropriate pharmacopeial quality characterization for the botanicals used as herbal medicines and dietary supplements. The monographs provide detailed specifications for identity, content of bioactive constituents or quality markers, and limits of contaminants, adulterants, and potentially toxic substances. Additional requirements such as labeling and packaging further contribute to preserve the quality of these products.

Conclusion: Compliance with pharmacopeial specifications should be required to ensure the reliability of botanical articles used for health care purposes.

Keywords: Botanical dietary supplements; Herbal medicines; High-performance liquid chromatography identification; High-performance thin-layer chromatography identification; Specifications for botanicals; United States Pharmacopeia.