Dynamics of clay-intercalated Ibuprofen studied by Solid State NMR

In designing drugdelivery systems with improved release properties and bioavailability, the dynamic features of the active pharmaceutical ingredient can be crucial for the final product properties. In this work, we aimed at obtaining the first characterization of the molecular dynamic properties of one of the most common nonsteroidalanti-inflammatory drug, ibuprofen, intercalated in hydrotalcite, an interesting inorganic carrier. By exploiting a variety of solid state NMR techniques, including 1H and 13C MAS spectra and T1 relaxation measurements, performed at variable temperature and carrying out a synergic analysis of all results, it has been possible to ascertain that the mobility of ibuprofenwithin the carrier is remarkably increased. In particular, strong indications have been obtained that ibuprofenmolecules, in addition to internal interconformational dynamics, experience an overall molecular motion. Also considering that ibuprofenis “anchored” to the charged surface of the hydrotalcitelayers...