Fundamental evaluation and optimization of porous spherical silica for developing functional fine particles via fluidized bed coating

Improved direct compression properties of Gardeniae Fructus water extract powders via fluid bed-mediated surface engineering

Direct compression (DC) attracts increasing attention for tablet manufacturing; however, its application in medicinal plant tablets is still extremely limited. In this work, eight kinds of the Gardeniae Fructus water extract powder (GF)-based composite particles (CPs) were prepared with different cohesive surface engineering materials, including dextran, inulin, hypromellose, and povidone, alone or in combination with mannitol and colloidal silica. Their physical properties and compacting parameters were characterized comprehensively. All the CPs showed marked improvement in tabletability, which is about 2-4 times higher than that of GF and physical mixtures (PMs). Specifically, the CPs showed a 7.45-26.48 times higher hardness value and a 1.26-2.74 times higher cohesiveness value than PMs. In addition, all the CPs (angle of repose being from 34.27° to 38.46°) showed better flowability than PMs (35.49° to 53.53°) and GF (51.86°). These results demonstrated that (i) fluid-bed coating was not a simple process of superposition and transmission of the physical properties of raw materials; and (ii) all the surface engineering materials studied could improve the DC properties of problematic GF to some degree. As a whole, through the design of fluid-bed coating CPs, qualified tablets with high GF loadings (up to 93%) were produced via DC.

The Fundamental and Functional Property Differences Between HPMC and PVP Co-Processed Herbal Particles Prepared by Fluid Bed Coating

Core-shell composite particles (CPs) are the most preferred choice for direct compaction (DC), but their application in herbal tablets is limited. Hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) are usually employed as the shell materials, but there are few, if any, researches exploring the different effects of HPMC and PVP on the properties of herbal CPs. In this study, the CPs containing HPMC (CP X-H) and CPs containing PVP (CP X-P) were prepared based on herbal powders (X). Their physical properties were characterized comprehensively. The differences in properties between CP X-H and CP X-P were explored, and their mechanism analysis was also performed profoundly. The results demonstrated that (i) CP X-H and CP X-P exhibited similar flowability; (ii) CP X-H generally exhibited better compactibility, larger particle size, and more uniform particle size distribution, and lower bulk density, tap density, and hygroscopicity than CP X-P; (iii) compared with the tablets produced with CP X-P, ones with CP X-H exhibited similar weight variation (%), lower friability, and longer disintegration time. The mechanism analysis manifested that the differences in physical properties between HPMC and PVP were the important and fundamental factors, which led to the differences in structure and surface morphology of particles, and in fundamental properties of CPs. These findings are beneficial to the development of herbal core-shell CPs for DC.