Distribution pattern and surface nature-mediated differential effects of hydrophilic and hydrophobic nano-silica on key direct compaction properties of Citri Reticulatae Pericarpium powder by co-processing

Study on Improving the Performance of Traditional Medicine Extracts with High Drug Loading Based on Co-spray Drying Technology

The purpose of this study is to develop modified particles with different structures to improve the flowability and compactibility of Liuwei Dihuang (LWDH) powder using co-spray drying technology, and to investigate the preparation mechanism of modified particles and their modified direct compaction (DC) properties. Moreover, tablets with high drug loading contents were also prepared. Particles were designed using polyvinylpyrrolidone (PVP K30) and hydroxypropyl methylcellulose (HPMC E3) as shell materials, and sodium bicarbonate (NaHCO3) and ammonium bicarbonate (NH4HCO3) as pore-forming agents. The porous particles (Ps), core-shell particles (CPs), and porous core-shell particles (PCPs) were prepared by co-spray drying technology. The key DC properties and texture properties of all the particles were measured and compared. The properties of co-spray drying liquid were also determined and analyzed. According to the results, Ps showed the least improvement in DC properties, followed by CPs, and PCPs showed a significant improvement. The modifier, because of its low surface tension, was wrapped in the outer layer to form a shell, and the pore-forming agent was thermally decomposed to produce pores, forming core-shell, porous, and porous core-shell composite structures. The smooth surface of the shell structure enhances fluidity, while the porous structure allows for greater compaction space, thereby improving DC properties during the compaction process.

Updates on applications of low-viscosity grade Hydroxypropyl methylcellulose in coprocessing for improvement of physical properties of pharmaceutical powders

Hydroxypropyl methylcellulose (HPMC) is an important polymeric excipient. Its versatility in terms of molecular weights and viscosity grades is the basis for its wide and successful application in the pharmaceutical industry. Low viscosity grades of HPMC (like E3 and E5) have been used as physical modifiers for pharmaceutical powders in recent years due to their unique physicochemical and biological properties (e.g., low surface tension, high T_g, strong hydrogen bonding ability, etc.). Such modification is the co-processing of HPMC with a drug/excipient to create composite particles (CPs) for the purpose of providing synergistic effects of functional improvement as well as of masking undesirable properties of the powder (e.g., flowability, compressibility, compactibility, solubility, stability, etc.). Therefore, given its irreplaceability and tremendous opportunities for future developments, this review summarized and updated studies on improving the functional properties of drugs and/or excipients by forming CPs with low-viscosity HPMC, analyzed and exploited the improvement mechanisms (e.g., improved surface properties, increased polarity, hydrogen bonding, etc.) for the further development of novel co-processed pharmaceutical powders containing HPMC. It also provides an outlook on the future applications of HPMC, aiming to provide a reference on the crucial role of HPMC in various areas for interested readers.

Surface Modifiers on Composite Particles for Direct Compaction

Direct compaction (DC) is considered to be the most effective method of tablet production. However, only a small number of the active pharmaceutical ingredients (APIs) can be successfully manufactured into tablets using DC since most APIs lack adequate functional properties to meet DC requirements. The use of suitable modifiers and appropriate co-processing technologies can provide a promising approach for the preparation of composite particles with high functional properties. The purpose of this review is to provide an overview and classification of different modifiers and their multiple combinations that may improve API tableting properties or prepare composite excipients with appropriate co-processed technology, as well as discuss the corresponding modification mechanism. Moreover, it provides solutions for selecting appropriate modifiers and co-processing technologies to prepare composite particles with improved properties.

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.