High pressure impregnation of vitamin D3 into polysaccharide aerogels using moderate and low temperatures

In this work polysaccharide alginate aerogels were applied as carriers for the high pressure impregnation of vitamin D-3. The supercritical impregnation technique has already been used for the impregnation of drugs into aerogels. However, to the best of our knowledge, subcritical liquid impregnation has not yet been employed for the impregnation of any drugs into any kind of porous carrier. Therefore, this is the first report on the use of liquid carbon dioxide for the impregnation of vitamin D-3 into aerogels. The impregnation experiments were carried out at 80 bar and at various temperatures: 35, 25, 15 and 5 degrees C, and kinetic curves were obtained. The influence of supercritical and liquid carbon dioxide on the structure of alginate aerogels during the impregnation process was examined throughout the characterisation of the samples. To evaluate the protection by impregnation into the aerogels, vitamin's D-3 stability in cold storage was tested. Finally, in-vitro dissolution testing was performed, and controlled release of the vitamin over a time span of 5-6 h was achieved. (C) 2016 Elsevier B.V. All rights reserved.