Preparation and Application of Shen Ling Cao Composite Particles with Different Structures Based on Co-Spray Drying

Objectives: Sen Ling Cao (SLC) is an excellent health food that has health-promoting functions, such as alleviating physical fatigue and boosting immune function. Currently, SLC is predominantly marketed and administered as an oral liquid, which suffers from the disadvantages of inconvenient transport and limited versatility. In this study, we investigated the preparation of direct compression (DC) tablets of SLC. Methods: Hydroxypropyl methylcellulose E3 (HPMC E3), polyvinylpyrrolidone K30 (PVP K30), hydroxypropyl cellulose EF (HPC EF), and maltodextrin (MD) were selected as modifying agents; and ammonium bicarbonate (NH₄HCO₃) and sodium bicarbonate (NaHCO₃) were employed as pore-forming agents. Co-spray drying was utilized to prepare 13 kinds of composite particles with different structures. Subsequently, their physical properties and compacting parameters were characterized comprehensively. Finally, the various composite particles were directly compacted into tablets to study the respective effects on the properties of DC tablets. Results: The results demonstrated that (i) the SLC composite particles have been successfully produced by co-spray drying, and processing involves physical changes; (ii) the tensile strength (TS) values of PCP-SLC-HPMC-NH₄HCO₃, PCP-SLC-PVP-NaHCO₃, PCP-SLC-HPC-NaHCO₃, and PCP-SLC-HPMC-NaHCO₃ were 9.8, 7.2, 8.3, and 7.7 times higher than that of SLC; (iii) all the modifiers studied could improve the DC properties of problematic SLC to some degree, and the combination of HPMC and NH₄HCO₃ showed to be the best to markedly improve both the compactibility and flowability of SLC. Conclusions: Overall, the design of porous composite particles, composite particles, and porous composite particles in this study successfully produced qualified tablets with high SLC loadings via DC. These findings are favorable for promoting the development and application of natural botanical tablets through DC.