**6. Therapeutic applications of drug repurposing in infectious diseases**

Drug repurposing strategy recently identified that the anthelmintic drug niclosamide (NCL) is a strong inhibitor of the 3OC12 − HSL-dependent QS system in *Pseudomonas aeruginosa* by inhibiting the LasR-dependent signaling leading to reduced virulence, and attenuated *P. aeruginosa*. Pulmonary administration is an ideal route to treat respiratory infections but the major obstacle in pulmonary administration of NCL was the achievement of appropriate particle size and its poor dissolution properties in alveolar fluids due to hydrophobicity. Hence, therapeutic applications of nanotechnology were employed to formulate NCL nano dry powders using high-pressure homogenization and spray drying technologies. Thus, repurposed drugs based on their pharmacokinetic profile may be modified in the form of nano-suspensions enhancing the drug's potential for the treatment of infectious diseases [23]. Similarly, synergistic drug combination along with antibiotics is a useful therapeutic option for various repurposed nonantibiotic drugs showing less potential against infections leading to reduced chances of attaining antibiotic resistance [24, 25].
