Preparation and characterization of raloxifene nanoparticles using Rapid Expansion of Supercritical Solution (RESS)

One of the key factors in drug's efficacy is the value of their bioavailability that increases by the reduction of particle size through improvement of dissolution rate. In this study, raloxifene particle size was reduced by Rapid Expansion of Supercritical Solution (RESS). The effect of extraction temperature (40–80 °C), extraction pressure (10–18 MPa) and spray distance (5–10 cm) were investigated on size and particle size distribution of the nanoparticles. Particles were characterized using X-ray diffraction (XRD), Fourier Transform Infrared Analysis (FTIR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS).The average size of the unprocessed raloxifene particles was 45.28 μm. After the process, depending on the experimental conditions, smaller particles were obtained, the smallest of which was 18.93 nm. In addition, dissolution rate study indicated that a 7-fold increase in dissolution rate could be obtained by particle size reduction of raloxifene using RESS. Response Surface Methodology was used for the optimization of the results and showed that the smallest particle size could be achieved at temperature of 50 °C, pressure of 17.7 MPa and spray distance of 10 cm.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Raloxifene is a poor water soluble and low bioavailable drug. ► Its particle size was reduced from 45 μm to 19 nm by RESS. ► Effect of spray distance, extraction temperature and pressure were examined. ► Raloxifene dissolution rate increased 7-fold after the process. ► RSM was used for optimization of the experimental conditions.