Polymeric drug nanoparticles prepared by an aerosol flow reactor method

Purpose. Our purpose was to study the possibility of using a novel method, namely, aerosol flow reactor method, for the preparation of drug-containing nanoparticles with varying amounts of drug and polymer. The physical properties of the prepared nanoparticles were analyzed. Methods. The nanoparticle size distributions were measured using differential mobility analyzer. The structure of the prepared nanoparticles was assessed by x-ray diffraction, differential scanning calorimetry, and electron microscopy. Drug release from the nanoparticles was analyzed. Results. The spherical particles produced showed a unimodal and lognormal size distribution, and the geometric number mean size of the nanoparticles could be varied between 90 and 200 nm. When the amount of drug in the polymeric matrix was small, the nanoparticles had a homogeneous, amorphous structure. Drug crystals were formed when the amount of drug was increased over the solubility limit of the drug into the polymer. The amounts of drug and polymer controlled the drug release from the nanoparticles. Conclusions. The aerosol flow reactor method was found to be able to produce homogeneous amorphous matrix-type nanoparticles that can directly be collected as dry powder.