Microparticles of soy lecithin formed by supercritical processes

Finely divided particles of phospholipids are used to form controlled drug delivery systems called liposomes. Conventional physicochemical methods for preparing these microparticles are hampered by a major drawback-the use of organic solvents that remain at few but inhibitory concentration in the fi nal product. This study aimed to propose an alternative method for preparin g microparticles of phospholipids starting from soy lecithin-the process ha d to be free of solvent or at least, the solvent had to be nontoxic. Two mi cronization techniques based on the use of supercritical carbon dioxide wer e investigated: the RESS and the SAS processes. The RESS process failed to separate the particles formed from the cosolvent. Performing the SAS proces s with ethanol as auxiliary solvent, enabled fine particles to form with si ze ranging from 1 to 40 mum. Particles were spherical and partly agglomerat ed and seemed to be free of solvent as shown by preliminary infrared analys is. (C) 2000 John Wiley & Sons, Inc.