Effect of Coaxial Nozzle on the Preparation of Drug-Loaded Polymer Microparticles Using Supercritical CO₂

In this study, gemcitabine-loaded poly(L-lactic acid) (L-PLA) nano- and microparticles were prepared using solution enhanced dispersion by supercritical fluids (SEDS) technique. Gemcitabine is a synthetic pyrimidine nucleoside analogue with a high antitumor efficacy for ovarian, breast bladder, and pancreatic cancer. The SEDS process is a modified supercriticalantisolvent (SAS) process, in which supercritical CO2 and polymer/drug solution are simultaneously introduced into a high-pressure vessel using a coaxial nozzle. The effects of CO2 flowrate, solution flowrate, temperature, pressure, polymer molecular weight and solution concentration on the morphology and drug entrapment efficiency of SEDS-processed particleswere investigated. The entrapment efficiency and in vitro release profiles of gemcitabine from microparticles were also determined using HPLC. Our study was focused on the comparison of SEDS with ASES process.