Furosemide (FSM) is a biopharmaceut

Furosemide (FSM) is a biopharmaceutical classification system (BCS) class IV drug, being a potent loop diureticused in the treatment of congestive heart failure and edema. Due to its low solubility and permeability, FSM isknown for exhibiting poor oral bioavailability. In order to overcome or even minimize these undesirable biopharmaceutical attributes, in this work we have focused on the development of more soluble and permeablemulticomponent solid forms of FSM. Using solvent evaporation as crystallization method, a salt and a cocrystalof FSM with imidazole (IMI) and 5-fluorocytosine (5FC) coformers, named FSM-IMI and FSM-5FC, respectively,were successfully prepared. A detailed structural study of these new solid forms was conducted using single andpowder X-ray diffraction (SCXRD, PXRD), Fourier Transform Infrared (FT-IR) and proton Nuclear MagneticResonance (1H NMR) spectroscopy and thermal analysis (thermogravimetry, differential scanning calorimetryand hot-stage microscopy). Both FSM-IMI and FSM-5FC showed substantial enhancements in the solubility (up118-fold), intrinsic dissolution (from 1.3 to 2.6-fold) and permeability (from 2.1 to 2.8-fold), when compared tothe pure FSM. These results demonstrate the potential of these new solid forms to increase the limited bioavailability of FSM