Pharmeuropa Text for Comment: HPTLC for Herbal Products

Pharmeuropa has announced the availability of a new text for comment. The new draft for chapter 2.8.25. High-performance thin-layer chromatography of herbal products expands its scope to include herbal drugs, herbal drug preparations, and herbal drugs for homoeopathic preparations and mother tinctures instead of herbal drugs and herbal drug preparations.

The text now provides detailed guidelines on the use of advanced High-Performance Thin-Layer Chromatography (HPTLC) techniques for quality control and the detection of adulterants in herbal products. Key changes and new parts focus on the following:

• Equipment
• Preparation of solutions
• Preparation of the chromatographic system
• Saturation of the chamber
• Development of the plate
• System suitability test
• Visual evaluation
• Quantitative evaluation

Concerning the system suitability test (SST), the briefing notes state the following; "The basis for developing system suitability tests is not restricted to the separation of only two substances that migrate closely but that are narrowly separable under the specified chromatographic conditions. Individual monographs may prescribe the use of HPTLC system suitability solution CRS as the reference solution for carrying out the system suitability test. This CRS is a solution of eight different organic compounds dissolved in methanol. It allows the verification of the adequate performance of the chromatographic system for the entire R_F range of a HPTLC plate, by yielding an even distribution over the whole R_F range of at least three of the eight constituents for a large variety of developing solvents covering a wide range of polarities and selectivities on silica gel 60 F₂₅₄. The evaluation is done at 254 nm without derivatisation, and the corresponding acceptance criteria are based on the position in the chromatogram of the zones due to some, or all, of the eight constituents, although it is possible that not all eight constituents will be separated."

The full text and further details on the revision can be found, after registration, on the Pharmeuropa website. The deadline for public comments is 31 December 2024.