WATER BINDING IN COMPOSITE SYSTEMS BASED ON MILLED MEDICINAL PLANTS AND NANOSILICA
The aim of the study was identifing the influence of wetting-drying compacted nanosilica particles on the binding of water by milled plant raw materials in neutral and acidic media. Flowers of <i>Hibiscus sabdariffa</i> and <i>Calendula officinalis</i> were used as the model materials. According to the microphotographs and low temperature <sup>1</sup>H NMR spectroscopy data, the silica film forms on the surface of the milled plant particles, and it can significantly influence their hydration. According to the suggested scheme, some of the water from the inner cavities of plant raw materials moves (as evidenced by the decreasing radius of water-filled pores) to the zone of contact of the composite components (the radius of clusters of adsorbed water increases). In studies of desorption of active substances from milled medicinal plants and their composites by the initial and wetting-drying compacted nanosilica, it has been shown that the formation of a composite significantly reduces the rate of desorption. Minimal desorption is observed in composites containing wetting-drying compacted nanosilica. The studied composite systems are promising for biomedical researches.