Abstract:
Microparticles containing antitubercular agent, Rifampicin, was prepared and evaluated for its suitability as respirable dry powder formulation for lung delivery. Chitosan solution containing rifampicin, lactose and leucine in different ratio was spray dried. Ascorbic acid was used in concentration of 200µg/ml as antioxidant. The other physical properties of prepared microparticles like Particle size, morphology, densities and aerodynamic diameter were determined. Solid state of microparticles was characterized by Differential scanning calorimetry (DSC) and X-ray diffraction studies. The fine particle fraction and emitted dose required for a good aerosol performance was determined by Andersen Cascade Impactor. Microparticle with maximum drug loading of 98.31 and particle size in range 5-7µm was obtained with % yield of ≤ 43 %. Satisfactory aerosol properties like FPF (47.29 %), emitted dose up to 92 % and theoretical aerodynamic diameter less than 3.62 µm were obtained. The in vitro drug release from chitosan microparticles was found to be slow and up to 68 to 84 % in 6 hrs. When drug release data were plotted in Ritger and Peppas model, all formulations except controlled formulation showed fickian diffusion kinetic. The present study revealed that the rifampicin loaded chitosan microparticles produced by spray drying showed good physicochemical properties deemed suitable for inhalation therapy.

Keywords: Respirable Dry Powder, Chitosan Microparticle, Rifampicin, Spray Drying.