Short Lecture "Quality of oral solid formulation of herbal medicinal products – a case study with Lavandula species products"

Several of the 39 Lavandula species, their hybrids and about 400 registered cultivars are important aromatic and medicinal plants in the phytopharmaceuticals, food, and cosmetics industry [1]. Lavandula angustifolia Mill. is used traditionally to treat restlessness, agitation, insomnia and intestinal discomfort linked to nervousness [2]. Silexan​, a high-quality lavender oil, is registered as a medicine for the treatment of anxiety disorders in several countries. The flower extract is used as an infusion to treat respiratory conditions. The oil is also used externally for scar and wound healing, in insect bites and burns, and for its aroma [2]. As of April 2023, 415 clinical trials with lavender as the investigational product were registered (https://trialsearch.who.int/). We evaluate the chemical profile and in vitro disintegration and dissolution of 55 products from Lavandula species, including different oral dosage forms of single and multi–ingredients with different regulatory statuses, assessing the authenticity and predicting their in vivo performance. The phytochemical analysis detected considerable variability of the marker compounds (e.g., linalool, linalyl acetate, and cineole) between products, with some containing ‘often/sometimes undeclared’ amounts of rapeseed and sunflower oils. Out of 43 oral solid formulations (19 soft gel, 16 hard shell, and 8 tablets), 16 failed the disintegration testing; 5 soft gel, 8 hard shell, and 3 tablets, respectively. Pass rates for gelatine- based capsules were higher than for non-gelatine (cellulose-based) capsules. This work is ongoing, and our findings will have implications for the interpretations of the efficacy and safety of phytopharmaceuticals used in clinical trials [3].

Funding This project was funded by Dr Willmar Schwabe GmbH & Co. KG, Germany, manufacturer of Silexan​ through a charitable donation. The donor had no influence on the analysis and interpretation of the data.

 

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Conflict of Interest

The authors declare no conflict of interest.

• References

• 1 Aprotosoaie AC, Gille E, Trifan A, Luca VS, Miron A.. Essential oils of Lavandula genus: a systematic review of their chemistry. Phytochemistry Reviews 2017; 16 (04) 761-99
• 2 Edwards SE, da Costa Rocha I, Williamson EM, Heinrich M.. Phytopharmacy: An evidence-based guide to herbal medicinal products. John Wiley & Sons; 2015
• 3 Heinrich M, Jalil B, Abdel-Tawab M, Echeverria J, Kulic Z, McGaw L. et al. Best Practice in the chemical characterisation of extracts used in pharmacological and toxicological research-The ConPhyMP-Guidelines. Frontiers in Pharmacology 2022; 13: 953205

Publication History

Article published online:
16 November 2023