Development of a method for obtaining dry extracts from liquid aqueous-alcoholic extracts

Introduction. Herbal medicines remain relevant today. One of the most promising dosage forms are dry extracts. Their production is difficult and in some cases requires expensive equipment (spray dryer, etc.). The aim of this work was to develop a method for producing dry extracts from liquid aqueous-alcoholic extracts.

Aim. The aim of this work was to develop a method for producing dry extracts from liquid aqueous-alcoholic extracts.

Materials and methods. The objects of the study were aqueous-alcoholic extracts with a wide range of ethyl alcohol concentrations: from 16.5 to 70 % (vol.) and the maximum spectrum of biologically active substances – Tonsilgon N drops; tincture containing an original phytocomposition (rhizomes with roots of Rhapontici cartamoidis, leaves of Bergeniae crassifoliae, flowers of Calendulae officinalis, herb of Flipendulae ulmariae); a mixture of tinctures from the rhizomes with roots of Valerianae officinalis and the herb Leonuri cardiaceae. To obtain a dry extract, a rotary evaporator was used, on which liquid herbal preparations were concentrated and dried in a drying cabinet at a temperature of 60 °C with multiple additions of a liquid immiscible with water – ethyl acetate until the required humidity was obtained. The most optimal drying option was selected based on the following parameters: sample volume, concentration time on a rotary evaporator, frequency of addition of ethyl acetate and its amount, the size of the evaporation bowls, as well as the technique for distributing the concentrated mass. The obtained extracts were standardized according to the following parameters: description, flowability, loss in mass on drying in accordance with the requirements of the relevant general pharmacopoeial articles, the content of residual organic solvents (ethyl acetate) was estimated by high-performance liquid chromatography with an ultraviolet detector.

Results and discussion. A method for obtaining dry extracts from liquid aqueous-alcoholic extracts was developed. Dry consistency and flowability were achieved using an evaporating bowl with a size of at least 6 with distribution of the thickened mass by rotational movements relative to the vertical and horizontal axes of the bowl using a celluloid plate and adding ethyl acetate in a volume of 50 % of the initial mass of the liquid aqueous-alcoholic extract. Such parameters as sample volume, thickening time on a rotary evaporator and the frequency of adding ethyl acetate depended on the initial volume content of ethyl alcohol. The obtained extracts had the property of flowability, the loss in mass on drying was less than 10 %, the ethyl acetate content was less than 0.5 %.

Conclusion. A method for obtaining a dry extract from aqueous-alcoholic extracts was developed.

1. Safonova N. V., Trofimova E. O. Market analysis of herbal remedies used for respiratory diseases. Remedum. 2022;26(1):4–11. (In Russ.) DOI: 10.32687/1561-5936-2022-26-1-4-11.

2. Gol’derova A. S., Voronov I. V., Fedorov I. A., Filippova G. V., Darkhanova V. G., Stroeva N. S., Egorov A. N., Gotovtsev R. A. Method for obtaining a biopreparation from Siberian Phlojodicarpus with antitumor activity. Patent RUS № 2818479 C1. 02.05.2024. Available at: https://rusneb.ru/catalog/000224_000128_0002818479_20240502_C1_RU/?ysclid=mdbhjqrrp258843937 Accessed: 20.07.2025. (In Russ.)

3. Aleksanyan I. Yu., Maksimenco Yu. A., Guba O. E., Feklunova Yu. S. Spray dryer. Tekhnologii pishchevoi i pererabatyvaiushchei promyshlennosti APK – produkty zdorovogo pitaniia. 2015;2(6):55–59. (In Russ.)

4. Chen Y., Wang Y., He L., Wang L., Zhao J., Yang Z., Li Q., Shi R. Supercritical CO2 extraction of terpenoids from Indocalamus latifolius leaves: optimization, purification, and antioxidant activity. Foods. 2024;13(11): 1719. DOI: 10.3390/foods13111719.

5. Purygin P. P., Terentyeva O. V., Balandina I. V., Komarova N. V., Koretskii S. V. Detection and isolation of antibacterial peptides from Galleria mellonella larval extracts. Vestnik of Samara State University. 2006;6(1):201–211. (In Russ.)

6. Kulikova N. E., Chernobrovina A. N., Roeva N. N., Popova O. Yu. Study of the evaporation process for obtaining concentrates from plant materials. Food Processing: Techniques and Technology. 2023;53(2):335–346. (In Russ.) DOI: 10.21603/2074-9414-2023-2-2438.

7. Avdeeva E. Yu., Skorokhodova M. G., Sheikin V. V., Kadyrova T. V., Belousov M. V. Technology of dry extract from the Filipendula ulmaria (L.) Maxim. and preliminary assessment of its safety profile. Drug development & registration. 2024;13(2):84–92. (In Russ.) DOI: 10.33380/2305-2066-2024-13-2-1682.

8. Bogdanova N. M. Lactase deficiency and intoleranceto lactose: the main factors of development and the principles of diet therapy. Medicine: theory and practice. 2020;4(1):62–70. (In Russ.)

9. Ergasheva Y., Maksudova F. Technology for developing the dry extract. Eurasian Journal of Medical and Natural Sciences. 2025;5(4 Part 2):7–13. (In Russ.)

10. Matiusha K., Grytsyk A., Hrytsyk R., Raal A., Koshovyi O. Phytochemical research and screening of pharmacological activity in Eryngium planum L. herb extracts. Applied Sciences. 2025;15(3):1433. DOI: 10.3390/app15031433.

11. Raoult F. M. Loi générale des tensions de vapeur des. C R Hebd Seances Acad Sci. 1886;104:1430–1433.

12. Dalton J. Essay IV. On the expansion of elastic fluids by heat. Mem Lit Phil Soc Manch. 1802;5(2):595–602.

13. Kurkin V. A. Pharmacognosy: a textbook for students of pharmaceutical universities (faculties): for students studying in the specialty 060108 (040500) – "Pharmacy". Samara: Ofort; 2007. 1239 p. (In Russ.)