Preparation and characterization of sustained release pirfenidone loaded microparticles for pulmonary drug delivery: Spray drying approach

Abstract

Pirfenidone (PFD) is a drug of choice for the treatment of idiopathic pulmonary fibrosis. For the preparation of sustained release microparticles of PFD, Ethyl cellulose (EC 300) with Eudragit RS 100 in combination was used as encapsulating agents. The 3-level 2-factorial design was employed for the design of experiments (DoE). The spray dried microparticles were studied for their particle size distribution, surface topography, drug entrapment, in-vitro drug release, and aerodynamic performance. Compatibility between drug and excipients were evaluated by Fourier Transform Infrared (FTIR) Spectroscopy and Differential Scanning Calorimetry (DSC). Particle morphology and size distribution were performed using Field Emission Scanning Electron Microscopy (FESEM) and Dynamic light scattering (DLS). The average particle size of the optimized PFD loaded formulation was found to be 3.99 μm. The surface topography study of the optimized formulation showed that the microparticles are nearly spherical with a smooth surface. In addition, the in-vitro aerosol performance was studied by Anderson cascade impactor and developed microparticles showed favorable aerodynamic performance (MMAD 4.25 μm) with narrow particle diameter distribution (GSD 1.52), therefore developed microparticles can be used as a dry powder for inhalation (DPI) for the targeted delivery to the lungs. In conclusion, sustained release microparticles of PFD were successfully prepared by the spray drying technique.