CHARACTERISTICS OF DENSE GAS ANTISOLVENT PRECIPITATION AND SCALE-UP CONSIDERATIONS
Microparticle production technique is presently a major development of dense gas antisolvent precipitation applications, mainly in the pharmaceutical, food, cosmetic and specialty chemical industries. In this paper the process flow schemes and characteristics of GAS(SAS),ASES,SEDS and PGSS are introduced respectively, both mono-constituent and composite microparticles, which make the controlled release of active components practicable, could be produced by using the four processes previously described. Comparatively speaking, the feasibility of producing dry uniformly sized micronised material by using dense gas antisolvent technology has been well established on laboratory or bench scale except for that specific experimental phenomena could not be explained satisfactorily.The relationship between particle size, morphology and operating conditions has not been exactly correlated yet.Translating these advantages to commereial scale remains a challenge for engineers. To date few models have been successfully applied to the above processes as relatively little is known about the nature of dense gas antisolvent precipitation.Models are correlative rather than predictive. The inherent relationship among unit dimension, construction of equipment, process parameters, particle size and morphology has not been established because the dominant controlling factors are not thoroughly understood. Based upon an analysis of these processes, the scale-up pathway, current issues relating to antisolvent micronisation techniques and the focus in further fudy are addressed.