Prof Dr. Takehisa Hanawa

Professor Dr. Takehisa Hanawa is recognized for his contributions to drug formulation and advanced pharmaceutical technology.

Strategies for Improving the Solubility of Poorly Water-Soluble Drugs

It is estimated that 30–40% of currently marketed pharmaceuticals are poorly water-soluble drugs classified as Class II or Class IV under the BCS classification system. Furthermore, 70–90% of new drug candidates are considered to be poorly water-soluble, making the improvement of water solubility in pharmaceuticals an urgent priority for formulation researchers. In this presentation, we will introduce two pharmaceutical engineering methods: the formation of nanoparticles via dry milling and a method utilizing porous adsorbent carriers. In this study, a ground mixture of commercially available rebamipide (RB) tablets and HPC-SSL was prepared by dry milling to obtain a dispersoid with high dispersion stability suitable for use in a mouthwash. Subsequently, the physicochemical properties of the mixture with HPC-SSL were compared with those of the powder obtained from pre-ground RB tablets. Co-grinding with HPC-SSL transformed RB into fine particles ranging from approximately 303.6 to 361.5 nm, and a tendency to prevent particle aggregation over time in solution was observed. The sample microparticles formed with HPC-SSL avoided aggregation on the mucosal surface for 24 hours and improved oral retention. The “sealed heating (SH) method” involves heating a mixture of a porous material and sublimed API in a sealed container. In this study, we focused on mesoporous silica (MPS-4R or -2R) as the porous material. The adsorption of ibuprofen (IBU) onto MPS was investigated using the SH method. PXRD analysis revealed that the IBU crystals were amorphized by the SH method. The dissolution rate of the SHM containing 10 wt.% IBU, 10 minutes after the start of the test, was approximately 2.7 times higher than that of the IBU crystals. These results indicate that the SH method is a novel technique for amorphizing poorly water-soluble drugs and improving their solubility without using organic solvents.