Development on porous particles of Pueraria lobatae Radix for improving its compactibility and dissolution

Herein, we report a study on the influence of particles having different porosities on tablet performance. The ethanol extract of Pueraria lobatae Radix (EPL) was chosen as the model drug. A series of porous EPL particles were prepared by co-spray drying EPL with different amounts of ammonium bicarbonate (NH₄HCO₃), and their powder properties (particle morphology, particle size, porosity, flowability, bulk density, and tap density) and tablet properties (tensile strength, E _sp, yield pressure, dissolution, etc.) were comparatively investigated. The results showed that there were significant differences in the fundamental and functional properties of the spray-dried and parent EPLs. First, the irregular and dense primary EPL particles were transformed into loose, hollow, and spheroidal particles via co-spray drying with NH₄HCO₃. Second, compared to parent EPL, porous EPLs showed a significant improvement (1.80-7.03 times) in compactibility. Third, the dissolution rates of porous EPLs were similar, and all were more than twice as fast as that of parent EPL. The increased porosity, on the one hand, led to the increase in interparticle and intraparticle bonding forces during tableting and, on the other hand, facilitated water intrusion into tablets for disintegration and dissolution. Porous particle design is therefore promising, especially for drugs with both poor compactibility and dissolution.