THERMAL STUDIES OF PHARMACEUTICAL-CLAY SYSTEMS .1. MONTMORILLONITE-BASED SYSTEMS

Pharmaceutical-clay systems, used as solar radiation shields, obtained by interaction of Na montmorillonite and several pharmaceuticals usin g two methods of preparation, have been studied. Samples have been pre pared by melting the drug onto the clay or by intimate mixing and grin ding of both. The shielding ability against solar radiation is improve d by use of these preparation methods. Differential thermal analysis a nd thermogravimetric analysis confirm the steady substitution of water molecules from the interlayer space of the clay by drug molecules, as the amount of the latter is increased. The melting method seems to fa cilitate access of the drug into the interlayer space of the clay.