e(III)-Based Layered Double Hydroxides Carrying Model Naproxenate Anions: Compositional and Structural Aspect

In this work, Al cation was gradually replaced by Fe-III in the composition of Layered Double Hydroxides (LDH) and systematically investigated for LDH application as drug carriers, ultimate aiming to improve their biointegration. The incorporation of Fe-III into LDH layers, as well the intercalation of organic anions in the iron-based materials, is challenging. Several studies approach the intercalation of non-steroidal anti-inflammatory drugs such as anionic naproxen (NAP) into Al-LDH. Thus, NAP was applied here as a model drug for the study of compositional and structural aspects of novel Fe-III-LDH carriers envisaging to shed light on the intercalation of other carboxylate drugs into these materials. LDH of general {[}M2FeyAl(1-y)(OH)(6)]A(n-) compositions (M-II=Mg or Zn; A(n-)=anion of charge n) were investigated using two synthetic methods for NAP intercalation. Full X-ray diffraction profile refinement and a crystal-geometrical reasoning were used to strengthen the results interpretation. Unlike coprecipitation, in which probably NAP complexation with Fe-III hinders LDH-NAP self-assembling, topotactic ion exchange demonstrated to be a potential approach. (AU)