Layered double hydroxides matrix as host for curcumin loading: structural and spectroscopic investigations

Curcumin, an important bioactive compound and natural photosensitizer, which exhibits various biological properties, was loaded into inorganic carriers MgAl/ZnAl layered double hydroxides (LDH). The supporting matrices were obtained by co-precipitation, and a surfactant was used for including the organic drug. The structural, morphological, and spectral properties of the obtained composites were followed by X-ray diffraction, FTIR, SEM, UV–Vis, and fluorescence spectroscopy in solid state and in different solvents. The prepared formulations, the curcumin-loaded carriers, were introduced in alcohol-aqueous mixtures and the effect of solvent on the spectral properties of the formulations was investigated. Interactions between the keto-enol group of the pigment and the metals in LDHs laminates as well as inter-molecular bonds between alcohols and curcumin were evidenced. As a consequence, it was concluded that the composition of the carrier as well as the nature of the solvent determine the structural changes of the formulations. MgAl-LDH in powder has better spectral characteristics in the low-energy range (UV–Vis and fluorescence) than ZnAl-LDH. Their spectra are altered when methanol and water are present in the solvent mixture. The released curcumin concentration is in the range for photosensitization applications. The results have potential utilizations in many fields such as food, pharmaceutical, and biology.