The peculiar dissolution behaviour of Piretanide hosted in layered double hydroxides

Layered double hydroxides (LDHs) are widely used as inorganic hosts for different applications, in particular for drug delivery. Piretanide, a poorly soluble diuretic drug, could benefit of the association with LDH for improving the dissolution rate and also for limiting the gastric irritation after its repeated administration thanks to natural antacid properties of LDH. In this paper, the hybrids compounds Piretanide-Mg3Al-LDH and Zn3Al-LDH were synthesized by co-precipitation method. The first proofs to demonstrate the successful intercalation came from X-ray powder diffraction (from hydroxide layers expansion with respect to LDH-carbonate), thermal analysis (from the absence of drug melting point in the hybrid compound) and infrared spectroscopy (from the absence of the carboxylic acid vibration in the hybrid). In addition, SEM microscopy/EDS microanalysis supported the formation of new entities. Both compounds showed a significant improvement of the drug dissolution rate, compared to the active alone, in biorelevant conditions simulating the oral administration.