Particle production for controlled drug release
Chemical Product Design and Engineering (CPD&E)
Chemical Product Design & Development - IV (CPD&E - 4)
Keywords: product technology, supercritical carbondioxide, micron particles, controlled release
Controlled release of medicine requires the application of micro particles. These particles should be in the range of 10 to 50 μm for oral administration, 1 to 5 μm for inhalation and subcuteanous applications and less than 1 μm when injected into the circulatory system. Moreover the particles should have a narrow size distribution and have a low organic solvent residual content. For the production of these particles the application of supercritical carbondioxide has several advantages above the classical processes like milling, freeze drying or precipitation and coacervation in organic solvents. Three different methods are possible for micro particle formation with supercritical solvents: precipitation by compressed anti-solvent (PCA), rapid expansion of supercritical solutions (RESS) and precipitation from gas saturated solutions (PGSS). In this last method we studied the behaviour of polyethylene-glycol which was first saturated with supercritical carbondioxide and than sprayed over a nozzle. The main effects of the supercritical carbon dioxide on the process was twofold: Due to a considerable viscosity drop (eight to ten fold) the spraying effect is far more effective than without CO2 and, because after pressure release the supercritical carbondioxide becomes gaseous, the polymer particles explode into even smaller particles. By changing temperature, pressure and molecular weight the size and morphology of the particles can be controlled. The size distribution of the particles obtained in this way appeared to be far more narrow than obtained by classical grinding. The product properties like solubility of drug and/or polymeric matrix material in the supercritical solvent determine which method (PCA, RESS or PGSS) can best be choosen.
Presented Thursday 20, 11:00 to 11:18, in session Chemical Product Design & Development - IV (CPD&E - 4).
