Industrial Crystallization

Abstract

Crystallization is one of the most widely used technologies in chemical industry; especially the food and pharmaceutical sectors are utilizing this unit operation for optimized separation, purification, and solid form selection. In addition to the unique advantage that crystallization can produce the crystalline product with a high purity, crystallization also plays an essential role in other aspects of the final product design. This is widely applied in the selection of the optimal solid forms in the pre-formulation and formulation of pharmaceutical products as well as in the optimization of the particulate properties, such as particle size and shape distributions. During the past decades, significantly increased efforts have been made towards the exploration of the solid form landscape that covers all possible solid structures, such as polymorphs, solvates, co-crystals, salts, and increasingly also amorphous phase. These increased activities are driven by the existing challenges in the pharmaceutical industry regarding the increased number of drug candidates with poor physicochemical profile, e.g., solubility in biological fluids. Meanwhile, the development of crystallization processes represents a complex and challenging issue, where several product properties, such as purity, crystal size and shape, and molecular level solid structure, have to be controlled simultaneously. The International Workshop on Industrial Crystallization (BIWIC) was initiated by Prof. Joachim Ulrich in 1990. A successful series of meetings have been held in the yearly workshop in Bremen, Delft, Halle, Rouen, Gyeongju, Cape Town, Magdeburg, Lappeenranta, and Tianjin. The 20th event, BIWIC 2013, was hosted by Dr. Haiyan Qu and Prof. Jukka Rantanen at the University of Southern Denmark in Odense, Denmark. Over the last two decades, BIWIC has developed into a highly successful and internationally recognized workshop for the industrial crystallization community. This special issue of Chemical Engineering & Technology combines selected contributions of BIWIC 2013 with other outstanding publications in the field of industrial crystallization. A wide range of interesting topics that address inter-disciplinary research issues is covered. In addition to the significant number of contributions devoted to the crystallization of different polymorphic compounds, solvates, and salts, novel formulation technologies involving the utilization of printable medicine products are also presented. Fundamental topics include nucleation and crystal growth kinetics, as well as modeling of crystallization processes. The new challenges in crystallization process control and scale up are discussed in the contributions dealing with in situ process monitoring and process analytical technology (PAT) system design. The crystallization of inorganics, organics, and proteins are covered in the articles concerned with the production of crystalline products in chemical food and pharmaceutical industry. Surprisingly, the so-called old topics are indeed the new topics, since the turn towards natural resources for chemicals, foods, and pharmaceutical materials lead to new challenges in separation and purification of those compounds. Crystallization is, at the end of the day, one of the most promising technologies for those challenges. Haiyan Qu, University of Southern Denmark Jukka Rantanen, University of Copenhagen Joachim Ulrich, Martin Luther University Halle-Wittenberg