Novel Environment-Friendly Spherical Agglomeration Process Designed by Crystal Self-Bridging Mechanism: A Case Study of Myo-Inositol

Environmental-friendly spherical crystallization technology has always been the focus in the field of crystallization. In this work, a novel crystal self-bridging (CSB) mechanism is proposed. In the absence of additives and organic solvents, preliminary agglomeration is generated through the adhesion force between crystals, and stable agglomeration is formed by the solid-bridge generated by crystal growth. The mechanism was explained from the perspective of the adhesion free energy. Myo-inositol (MI) was selected as the research object, and then a spherical agglomeration process was developed based on the CSB mechanism. Based on detailed experiments, we found that the seed size should be smaller than 100 μm (150 mesh). In addition, the optimal supersaturation ratio and suspension density should be 1.25 and 80 kg/m³, respectively. A fluidized bed crystallizer was used to enhance the crystallization process. Strategies of particle size control were proposed, and prediction equations for particle size were provided. The obtained spherical MI was compared with powdered and flaky MI, and then it was demonstrated that the spherical MI was excellent in terms of morphology, particle size distribution, flowability indicators, anticaking performance, and dissolution rate. The spherical particles of choline tartrate, niacinamide, and vitamin B1 were successfully prepared according to a CSB mechanism, so the universality of this mechanism was demonstrated. The results of this work provide effective guidance for improving the particle size and powder properties of MI and contribute to the promotion of the CSB mechanism to other systems.