医薬品工業

Numerical simulation of the particulate flows has become possible by using discrete element method (DEM) with high performance computers. Calculations of particle motion in three kinds of pharmaceutical apparatus done by the author are reviewed. A centrifugal tumbling granulater, a rotating vessel type mixer and a screw feeder are dealt with. The present simulations predict well the realistic particulate flows. Pharmaceutical industries manufacture products which affect human life. Therefore it is necessary to make the process validation which guarantees the security of life and the effect of a medicine. It is important to know the behavior of particles in detail in order to control the quality 01 pharmaceuticals. The numerical simulation makes it possible to know the detailed information such as the three dimensional particle behavior, the interaction between particles and the effect of condition of equipment. These information is helpful in deepening out understanding powder processes.

Supercritical carbon dioxide is expected as a solvent in nano-scale material preparations, such as rapid expansion of supercritical solutions (RESS), supercritical anti-solvent (SAS) precipitation, and supercritical solvent impregnation (SSI) due to the unique properties of carbon dioxide, non toxic, inflammable, and mild critical temperature and pressure 304.2 K and 7.3 MPa, respectively. In this work, the ophthalmic drug delivery systems were prepared by SSI method using carbon dioxide. The effects of water in SSI process on the drug release profile from the prepared drug delivery system were investigated. The knowledge of the solid-liquid-gas equilibria is very important for the process design in SSI process. The prediction model of the solid-liquid-gas in supercritical carbon dioxide mixture are also developed by using the equation of state combined with the molecular information, molecular surface charge density, surface area, and volume obtained from the quantum calculations.

To control safe administration of injection product, we should carefully handle foreign matters. Hospital sometimes encountered cases where insoluble matter formed during the preparation of injections. In order to deal with this situation, we discussed the mechanism of formation of the insoluble matter and countermeasures on manufacturing process. Insoluble matter was a critical problem for quality of drug product of injections. In this report, the review for general approach for the foreign matters on injection product was reported.

In this paper, we present numerical studies on multiphase flows related to food and pharmaceutical applications, focusing on the Discrete Element Method (DEM) and solid–fluid interaction simulations using the DEM. Specifically, we describe numerical models of the DEM coupled with the Volume-of-Fluid method and the DEM coupled with the Lattice Boltzmann Method, along with their application examples. In addition, we present the studies regarding the Reduced-Order Model based on Proper Orthogonal Decomposition.

Vacuum freeze-drying is known as one of the most effective drying methods for maintaining quality among the many drying techniques. The main feature of freeze-drying is that it uses the sublimation of ice as the primary principle of dehydration. In this paper, the author will consider how freeze-drying process can be linked from a device perspective and a product quality perspective in terms of “fluid flow”. The drying rate is determined by the balance between the sublimation rate, water vapor transfer within the material, the water vapor velocity in the dryer, and the frosting velocity on the cold trap. When the water vapor velocity within the device reaches Mach 1, it enters a choked flow state. Therefore, the conductance of the device and the performance of the cold trap are critical factors determining the drying performance. During the freeze-drying process, when the product temperature remains above the glass transition temperature of the freeze-concentrated phase, the collapse of product occurs. The degree of collapse is one of the major factors affecting product quality (product shrinkage, rehydration ability, inactivation of active substances, etc.), but establishing a quantitative evaluation method for this remains a significant challenge. This study presents the results of an analysis using CFD simulation to investigate how fluid flow during the drying process determines the degree of collapse.