Layered solids as a “molecular container” for pharmaceutical agents:<scp>l</scp>-tyrosine-intercalated layered double hydroxides

Abstract

L-Tyrosine has been intercalated into NiAl, MgAl and ZnAl layered double hydroxides by coprecipitation. The structure and composition of the intercalated materials have been characterized by X-ray diffraction (XRD) and elemental analysis. It is found that intercalation can inhibit racemization of L-tyrosine under the influence of sunlight, high temperature or ultraviolet light. Therefore, this layered material may have potential application as a “molecular container” for storing or transporting unstable chiral biomolecules or pharmaceutical agents. In addition, the thermal decomposition of the L-tyrosine intercalated NiAl-LDH has been investigated in detail by means of in situ HT-XRD, in situ FT-IR and TG-DTA. Loss of interlayer water occurs between room temperature and 150 °C while decomposition of intercalated L-tyrosine and dehydroxylation of the host layers begin at about 250 °C and 300 °C respectively.