The aim of the study was to prepare dry powder formulation of Ethionamide loaded polymeric microparticles for pulmonary delivery in effective treatment of multi drug resistant tuberculosis (MDR-TB). The microparticles were prepared by spray drying method using chitosan and hydroxy propyl methyl cellulose (HPMC) as biocompatible polymers. The microparticles and microparticle blend with lactose (Inhalac 230) were investigated for its aerosolization properties like emitted dose, mass median aerodynamic diameter, fine particle fraction, geometric standard deviation. The spray drying method produced rough surfaced microparticles under the size range of 8.5μm. Mass median aerodynamic diameter obtained for all formulation ranged in 2.28 μm to 3.33 μm and fine particle fraction in between 54.58 ± 5.16 to 75.74 ± 3.48. The lowest tapped density value obtained was 0.096 g/cm2 belong to formulation coded EM1. In vitro deposition studies using cascade impactor showed emitted dose of > 97% for all batches. The polymeric microparticles produced by spray drying technique showed promising particle characteristics suitable for inhalation with Fine particle fraction (75.74 ± 3.48) of total emitted dose, after blending with lactose. The blending of the microparticles with Inhalac 230 allowed the fine particle fraction values to increase by increasing the dispersibility of powder on inspiration.
