The aim of this work was to evaluate the feasibility of using solid lipid particles of glyceryl monostearate, produced using supercritical fluids, as carriers for active substances. Studies of melting point depression were carried out to pressures up to 24 MPa and the solubility of carbon dioxide in the lipid matrix was measured for three different temperatures in a range from 10 to 20 MPa. This matrix was then processed by PGSS(R) technique (particles from gas saturated solutions) with and without active substance. Caffeine was used as a model molecule. The particles produced were analyzed by laser diffraction for particle size distribution and by SEM (scanning electron microscopy) for morphology assessment. The particles loaded with caffeine were also analyzed by HPLC (high performance liquid chromatography). (C) 2007 Elsevier B.V. All rights reserved.