稠密气体抗溶剂沉淀的过程特征及其放大中的若干思考

CHARACTERISTICS OF DENSE GAS ANTISOLVENT PRECIPITATION AND SCALE-UP CONSIDERATIONS

稠密气体抗溶剂沉淀在微粒制备中得到广泛应用 ,主要用于药物、食品、化妆品和一系列精细化学品中 .介绍了GAS(SAS) ,ASES ,SEDS和PGSS等过程的流程和特征 .上述工艺不仅可以制备单组分微粒 ,还可以制备复合微粒 ,为活性物质的成功缓慢释放创造了条件 .相对而言 ,稠密气体抗溶剂沉淀的实验室规模制备微粒已较成熟 ,但对有些实验现象尚难给出满意的解释 ,操作条件与产物粒径和形态间的比较准确的关系也尚未建立 ,距放大到工业规模形成生产力尚有相当大的差距 ,主要表现在缺乏定量描述过程的模型 ,即使是关联模型也鲜见报道 ,更不要说预测模型 .因此难以建立在装置尺寸和结构与过程参数以及产品尺寸和形态间的有效联系 .究其原因还是应用基础研究不足 ,对过程实质理解不深之故 .在分析过程特征的基础上 ,讨论了过程放大的途径以及目前存在的问题和今后开发研究中应着重关注的各个层面 .

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.