Research on the powder classification and the key parameters affecting tablet qualities for direct compaction based on powder functional properties.

• A classification method was established based on the functional parameters of powder; • w , a , k G , y 0 , k a , k b , b , k FES , k E3 are considered as key functional parameters; • The properties of each category of powder were analyzed in detail; • b is considered the most critical functional parameter affecting tablet quality; • In addition, w , k a , k G , and a related parameter affect the qualities of the tablet. Direct compaction (DC) is the ideal method for tablet production. However, DC requires the highest quality powder functional properties, such as good flowability, compressibility, compactibility, and appropriate elasticity. In the present study, 24 types of natural plant product (NPP) powders, prepared using three commonly used methods, and 18 types of fillers were evaluated for their fundamental and functional properties. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to classify the powders and analyze the characteristics of each category of powder, based on functional properties. Partial least squares (PLS) regression models were established to predict the tensile strength (TS), ejection force (EF), disintegration time (DT), and solid fraction (SF) based on the powder's functional properties. The results show that: (i) Except for the direct pulverization powder, the fundamental properties among the NPP powders were similar; however, the functional properties were quite different; (ii) The powders could be classified well based on their functional parameters (w , a , k G , y 0 , k a , k b , b , k FES , k E3). The order of powders suitable for DC is Group 4 > Group 5 > Group 2 > Group 3 > Group 1; (iii) The compressibility and compactibility of the powder are beneficial to the TS and EF of the tablet. The compressibility of the powders correlated negatively with DT; nevertheless, the compactibility correlated positively with DT and SF. The true density (ρ true), median particle size (D 0.5) of the powders correlated negatively with SF. Overall, this study systematically evaluated the properties of commonly used NPP powders and fillers and found the key properties that affect the quality of tablets. [ABSTRACT FROM AUTHOR]