Layered double hydroxide and sulindac coiled and scrolled nanoassemblies for storage and drug release

Abstract

Sulindac, a non-steroidal anti-inflammatory of the indene acetic acid class, was immobilized inside layered double hydroxide Mg₂Al and Zn₂Al (LDH) nanovessels through a one pot reaction. LDH–drug materials were characterized by chemical elemental analysis, X-ray diffraction (XRD) (one dimensional electron distribution along the c-stacking axis, pair distribution function analysis), scanning and transmission electron microscopies, mass coupled thermal analyses, vibrational infrared and Raman spectroscopies, and solid state ¹³C NMR. Density Functional Theory (DFT) calculations were performed for sulindac (protonated and deprotonated forms) with the aim to assign the LDH–drug spectroscopic results. All converge towards a spatial organization of interleaved sulindac molecules close to that reported for the pristine polymorph II crystal structure. Of relevance for human treatment because of its biocompatibility and non-immunogenic effect, in vitro sulindac release experiments were performed in a phosphate buffer mimicking biological fluids and release profiles were refined using kinetic models.