Production of Lipid Microparticles Magnetically Active by a Supercritical Fluid-Based Process

An original technique, based on supercriticalCO2and on the particles from gas saturated solution (PGSS) micronization method, was developed to obtain magnetically active lipid microparticles. Magnetite nanoparticles (MNPs) were encapsulated into triestearin and phosphatidylcholine mixtures to increase their biocompatibility for future applications in the fields of biomedical diagnostics and therapeutic medications. The lipid particles produced were characterized to determine size and size distribution, and to confirm the encapsulation of MNP. The mean size was in the range of 200–800 nm. The possibility to drive these magnetically active particles by an external magnet was demonstrated in a simple apparatus simulating a vessel of the circulatory system. The results obtained indicate that the modified PGSS technique is suitable to produce lipid microparticles with magnetic activity for possible use in medical applications.

Micronization processes with supercritical fluids: fundamentals and mechanisms

Supercritical fluid techniques for materials precipitation have been proposed as an alternative to conventional precipitation processes as they allow to improve the performance of these processes in terms of reduction of particle size and control of morphology and particle size distribution, without degradation or contamination of the product. These techniques have received much attention during the last years, and their feasibility and performance have been experimentally demonstrated for many substances. One of the main pending tasks is the development of a systematic procedure for the design and scale-up of these processes. This requires not only empirical knowledge, but also information about the fundamentals of the process. This work aims to review the published literature dealing with a fundamental investigation or modeling of supercritical fluid precipitation processes.