SOME PHYSICOCHEMICAL PROPERTIES OF GEORGIAN BENTONITE CLAY

Abstract

Clay minerals are known as biocompatible materials and have been utilized for medicinal aims from long ago. Currently, bentonite clays have also been widely investigated for broad spectrum of new applications in many biomedical spheres due to their unique properties - expansion and adsorption abilities - which are very useful in pharmaceutics, cosmetics, drug delivery systems and tissue engineering. Swelling has a significant impact on the rheological and physical properties of clay. It depends on many factors including temperature, pH, and polarity. In addition, since bentonites have negative surface charge they possess high adsorption ability for cationic elements. The priority task at the I. Kutateladze Institute of Pharmacochemistry TSMU is to extend the biopharmaceutical application of Georgian bentonite clay. Several semisolid formulations were proposed on the bases of the preparation - Tikha Ascane (TA), received from the clay of Askana Deposit (Ozurgeti region of Georgia). In this study we investigated the swelling capability of TA in the presence of different temperatures, polarities and pH; the interaction behaviour of bentonite with cationic compounds was also evaluated. As many researches are focused on the combination clay minerals with cationic polymers for the preparation of effective therapeutic systems, we examined the suitability of TA as a substrate for the obtaining hybrid composites with biopolymer Chitosan (CS). The samples were characterized by examining FTIR spectra and morphology. The obtained data indicate that swelling capability of TA is affected by temperature, pH, and polarity of solutions.  FTIR analysis showed that cationic drug and polymer (CS) can be successfully incorporated in TA through adsorption and formation chemical bonds. Microscopic analyses demonstrated homogeneity of TA-CS composites. These results will be used in future for preparing drug - clay or drug - polymer composites based on TA for biomedical application.