Simple and scalable method for peptide inhalable powder production

The aim of this work was to produce capreomycin dry powder and capreomycin loaded PLGA microparticles intended for tuberculosis inhalation therapy, using simple and scalable methods. Capreomycin physico-chemical characteristics have been modified by hydrophobic ion pairing with oleate. The powder suspension was processed by high pressure homogenization and spray-dried. Spray-drying was also used to prepare capreomycin oleate (CO) loaded PLGA microparticles. CO powder was suspended in the organic phase containing PLGA and the suspension was spray-dried. Particle dimensions were determined using photon correlation spectroscopy and Accusizer C770. Morphology was investigated by scanning electron microscopy (SEM) and capreomycin content by spectrophotometry. Capreomycin properties were modified to increase polymeric microparticle content and obtain respirable CO powder. High pressure homogenization allowed to reduce CO particle dimensions obtaining a population in the micrometric (6.18 μm) and one in the nanometric (∼317 nm) range. SEM pictures showed not perfectly spherical particles with a wrinkled surface, generally suitable for inhalation. PLGA particles were characterized by a high encapsulation efficiency (about 90%) and dimensions (∼6.69 μm) suitable for inhalation. Concluding, two different formulations were successfully developed for capreomycin pulmonary delivery. The hydrophobic ion pair strategy led to a noticeable drug content increase.