Preparation and Evaluation of Pirfenidone Dry Powder by Spray Drying Technology

Abstract

Inhalation of pirfenidone is one of the possible methods for effective treatment of idiopathic pulmonary fibrosis. In this study, we attempted to prepare inhaled pirfenidone dry powder through reasonable design of the precursor formulation and parameter adjustment of the spray drying process. The mechanism of polyvinyl alcohol (PVA) polymer as surfactant is used to assist the dissolution of pirfenidone in water, instead of using organic solvents (such as ethanol and methanol) for dissolution, so as to reduce the production explosion-proof requirements and avoid safety problems that may be caused by solvent residues. Leucine is first enriched and crystallized on the surface of particles and then condenses into a hydrophobic shell which collapses to form wrinkles to reduce the cohesion between particles. When the solvent is water, pirfenidone: polyvinyl alcohol: leucine=2:1:3, and the inlet temperature is 120 °C, the content of the active pharmaceutical ingredient (API) in the particles is 40.7%, and the relative content reaches 81.4% with a fraction of fine particles (FPF) of 26.2%, which represents good drug loading and inhalation performance.