2005 Volume 53 Issue 8 Pages 1025-1028
Rapid expansion of supercritical solutions (RESS) technique was applied for the preparation of phenylbutazone fine particles. The operating temperature and pressure affected the yield of the drug fine particles, which was evaluated by dissolving the sprayed product of drug into ethanol. Effect of pre- and post-expansion conditions on the particle size distribution of phenylbutazone was investigated and the smallest sample (mean particle size: 1.59 μm) was obtained when the RESS method was operated at a pressure of 26 MPa combined with a temperature of 32 °C. Physicochemical properties of the fine particles were investigated by powder X-ray diffraction and differential scanning calorimetry. It was found that the phenylbutazone fine particles obtained were meta-stable β form under the experimental conditions tested, suggesting polymorphic transformation during the RESS process.
