Current Requirements for the Degree of Fineness of Herbal Substances and Herbal Medicinal Products

The introduction of monographs on new types of herbal substances, which were not included in the previous editions of the State Pharmacopoeia of the Russian Federation (Ph. Rus.), and the introduction of the new powder dosage form of herbal medicinal products require alignment of requirements for the degree of fineness of medicinal products. The aim of the study was to compare Russian and foreign pharmacopoeial requirements for the degree of fineness of herbal substances and herbal medicinal products. The analysis demonstrated that in the case of cut herbal substances and powder, the Ph. Rus., XIV edition, establishes limits for the percent of particles that pass through and particles that are retained by a sieve with a specified pore diameter. In the case of whole herbal substances, the Ph. Rus. establishes limits for the percent of particles that pass through a sieve with a specified pore diameter. The monographs of the world leading pharmacopoeias include general requirements for the size of particles in all powders produced from chemically synthesized substances, as well as from naturally occurring and mineral substances, while individual monographs have no requirements for the degree of fineness of herbal substances. The national pharmacopoeias of the Eurasian Economic Union member states also include requirements for the degree of fineness of herbal substances, but they are not sufficient. The results of the analysis of the established limits demonstrate the need to change the controlled size of small and large particles for some types of herbal substances.

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Quantitative Removal of Pyrrolizidine Alkaloids from Essential Oils by the Hydrodistillation Step in Their Manufacturing Process

Planta Medica ◽

10.1055/a-1534-6928 ◽

2021 ◽

Author(s):

David S. Giera ◽

Michael Preisitsch ◽

Hugues Brevard ◽

Jörn Nemetz

Keyword(s):

Essential Oils ◽

Manufacturing Process ◽

Pyrrolizidine Alkaloids ◽

Pyrrolizidine Alkaloid ◽

Medicinal Products ◽

Herbal Medicinal Products ◽

Naturally Occurring ◽

Herbal Medicinal ◽

Set Up ◽

Theoretical Considerations

AbstractPyrrolizidine alkaloids are naturally occurring toxins produced by certain weeds that can, if accidentally co-harvested, contaminate plant-based food, feed, and herbal medicinal products. Focusing on herbal medicinal products, the presence of pyrrolizidine alkaloids is restricted by regulatory prescribed thresholds to assure patient safety. Among the multitude of different herbal active substances utilized in herbal medicinal products, the class of pharmaceutically effective essential oils is considered to exhibit a negligible contribution to pyrrolizidine alkaloid contamination. Within the present investigation, this hypothesis should be scientifically scrutinized. For this purpose, an experimental set-up was chosen that reproduces the typical manufacturing step of hydrodistillation. Essential oils of eucalyptus and lemon were selected exemplarily and spiked with 3 representative pyrrolizidine alkaloids (retrorsine, retrorsine-N-oxide, and lycopsamine), whereupon hydrodistillation was performed. Analysis of the resulting distillates by LC-MS/MS proved that artificially added pyrrolizidine alkaloids were removed completely. Moreover, quantitative pyrrolizidine alkaloid recovery in the aqueous phases was observed. Hence, it was experimentally confirmed that herbal medicinal products employing hydrodistilled essential oils of pharmaceutical quality are intrinsically free of pyrrolizidine alkaloids due to the particularities of their manufacturing process. Furthermore, it can be concluded from theoretical considerations that essential oils produced by cold pressing have a negligible risk of carrying pyrrolizidine alkaloid contamination. Our findings provide a strong indication that the requirement for analytical pyrrolizidine alkaloid testing of essential oils for pharmaceutical use should be fundamentally reconsidered.

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