Spray-dried particles as pulmonary delivery system of anti-tubercular drugs: design, optimization, in vitro and in vivo evaluation.

Currently, one-third of the world's population is infected with tuberculosis (TB) mainly spread by inhalation of the tubercle bacilli, Mycobacterium tuberculosis. Patient non-compliance is the major reason for failure of anti-tubercular drugs (ATDs) chemotherapy due to multidrug administration for longer duration of time period. The main aim of current research study was to develop and characterize inhalable spray-dried particles for pulmonary delivery of ATDs, i.e., rifampicin (RIF) and isoniazid (INH). ATDs-loaded alginate particles were prepared by ionotropic gelation technique followed by spray drying and characterized on the basis of various evaluation parameters. Results showed that the optimized spray-dried particles were found to be spherical in shape with excellent flow properties. The drug release showed the biphasic pattern of release, i.e., initial burst (30-40% up to 4 h) followed by a sustained release pattern (90% up to 60 h). Optimized formulations exhibited lower cytotoxicity and excellent lung uptake up to 8 h. Optimized formulation also showed higher rate and extent of drug uptake by lungs due to preferential phagocytosis be macrophage. In future, alginate particles could be a promising carrier for targeted delivery of ATDs to alveolar macrophages for efficient management of TB.