A Natural Triterpenoid Saponin as Multifunctional Stabilizer for Drug Nanosuspension Powder.

The objective of this study is to prepare a novel drug nanosuspension modified by a natural triterpenoid saponin (glycyrrhizin (GZ)) and evaluate its stability and redispersibility. A poorly soluble drug (andrographolide (AGE)) was used as a model drug. AGE nanosuspensions (AGE-NS) using GZ as natural stabilizer with mean particle size of 487 nm were firstly prepared by homogenization and converted into dried AGE nanosuspension powder (AGE-NP) by freeze-drying. It was found that GZ was able to prevent the aggregation of AGE nanocrystals and the freeze-dried AGE-NP could easily redisperse back to AGE-NS. It was related with special properties of GZ that possessed the interfacial property (37.02 ± 0.29 N/m) and electrostatic effect (-43.6 ± 0.9 mV) and could entrap AGE nanocrystals into its network structure. The freeze-dried AGE-NP/GZ exhibited excellent performance, compared with those combined with trehalose as matrix formers. The powder X-ray diffraction result demonstrated that GZ did not alter the AGE crystal state. The dissolution of AGE-NP/GZ (99.87%) was significantly enhanced, compared with the coarse AGE (42.35%). This study demonstrated that GZ could be used as a novel multifunctional stabilizer for production of drug nanosuspensions and provided a promising basis for further formulation development of poorly soluble drug.