Supramolecular complexes of maltodextrin and furosemide polymorphs: a new approach for delivery systems

We present new supramolecular complexes of two different solid forms of furosemide (I or II) with maltodextrin, in order to explore their application as delivery systems improving the bioavailability of the drug. The complexation in solution was evaluated by 1H nuclear magnetic resonance experiments and phase solubility studies. The products in solid state were exhaustively characterized by using spectroscopic techniques (13C solid state nuclear magnetic resonance, infrared, scanning electron microscopy, X-ray powder diffractometry) and thermal analysis. 1H relaxation times experiments gave further support in distinguishing the new solid forms. Dissolution studies in simulated gastric fluid showed that both supramolecular complexes presented significant increase in the dissolution, while the corresponding physical mixtures exhibited the most discriminating conditions between the furosemide forms I and II. Our results suggest the enhancement of the solubility and the dissolution of furosemide in the new complexes, making them promising candidates for the preparation of alternative matrices in oral pharmaceutical formulations.