The effects of lubrication on the compaction and post-compaction properties of directly compressible maltodextrins

Abstract The effects of various concentrations of magnesium stearate as a tablet lubricant on three types of maltodextrins were investigated. The maltodextrins were physically processed by the methods of spray drying, fluidized bed agglomeration, and roller compaction were compared for their compaction and post-compaction properties. The compaction tests were performed using a 10.3 mm round tooling in conjunction with an Integrated Compaction Research System operating at a constant punch velocity of 100 mm/s. The lubricant sensitivity of the materials were determined using the R values (i.e. the ratio of the maximum lower punch force to the maximum upper punch force). The R values for the compacts of all types of maltodextrin reached a plateau when the magnesium stearate concentration was 0.5% (w/w) or higher. The compaction properties of the materials were studied by using the total work of compaction (TWC) and average power consumption (APC) parameters, both of which decreased with an increase in lubricant concentration due to decreased particle cohesiveness. The compaction time data, which were analyzed by dividing the compaction period into four regions, exhibited correlations with the TWC and APC values. The crushing strength of the compacts exhibited a decrease as the lubricant concentration was increased, which was in agreement with the TWC and APC data. The compacts of the maltodextrins generally experienced increased tablet porosity with an increase in lubrication concentration with the exception of one type of maltodextrin which was processed by the roller compaction method. The compacts of the latter were also stronger and less sensitive to lubrication than those of the other maltodextrins examined. In this study, dicalcium phosphate, which is a lubrication insensitive material, was also used as a ‘reference material’.