Rifampicin‐Loaded Nano‐in‐Microparticles (Trojan Particles) as a Pulmonary Delivery System for Tuberculosis Treatment

Abstract The oral rifampicin (RIF) dosage forms possess various side effects and limited efficacy for tuberculosis treatment. Thus, this work developed the nano‐in‐microparticles containing RIF (trojan nRIF) as a novel pulmonary delivery system. The RIF‐loaded nanoparticles (nRIF) were prepared by self‐assembly polyelectrolyte complexation between lecithin and chitosan, whereas the trojan nRIF were formulated by spray‐drying method of nRIF and mannitol/maltodextrin. The nRIF had a spherical shape with sizes of 86–126 nm, zeta potentials of 24–39 mV, entrapment efficiencies of 44–80 %, and drug loading capacities of 13–42 %. The RIF release from nRIF occurred in two stages, the initially rapid release stage and the controlled release stage upto 96 h, followed the Higuchi model. The trojan nRIF possessed the mass median aerodynamic diameter of 3.7–4.6 μm, fine particle fraction of 34–40 %, and alveolar fraction of 17–21 %. Compared to mannitol, maltodextrin was a superior carrier for nRIF, which yielded better aerodynamic properties and RIF was mainly stayed in the amorphous form. Moreover, using the scanning electron microscopy, the nano‐in‐microparticles were clearly observed with hollow structure. Finally, the trojan nRIF could preserve the physical properties of the encapsulated nRIF. In summary, the trojan nRIF could become a potential inhalation anti‐tuberculosis product.