Adsorption of Melted Drugs onto Smectite

Montmorillonite, a 2:1 clay mineral, is known to accommodate different organic substances within its interlayer space to form intercalation compounds, which have received much attention because of their stability and physicochemical properties. Its use as a drug carrier is widely studied, as the location of the drug molecules within the interlayer space of the clay may modify the suitability of some drugs for biological use (Grim 1962; Theng 1974; Grim and Gtiven 1978; Porubcan et al. 1979; Browne et al. 1980; Hermosfn et al. 1981; White and Hem 1983; Forteza et al. 1989). Usually, intercalation is achieved by adsorption from aqueous solutions of the drug, but some authors have recently reported on alternative methods that are faster, cleaner and cheaper, such as mechanically grinding a mixture of the drug and the clay (Vicente et al. 1989; Ogawa et al. 1989, 1990a, 1990b, 1991). Bujdfik and Slosiarikov~ (1992) have reported intercalation of octadecylamine into montmorillonite by solid state reaction. Further intercalation was observed after melting of octadecylamine, but was followed with partial decomposition. We report intercalation of two different drugs, currently used as sunburn protectors, into the interlayer space of montmorillonite by melting, without any decomposition.