The effect of binary mixture composition and magnesium stearate concentration on the Hiestand Tableting Indices and other related mechanical properties.

Maltodextrins were chosen as model excipients because maltodextrins possess a series of molecular weights that showed systematically changing consolidation mechanisms. As maltodextrin molecular weight increases, the plasticity of the material increases. Three commercial grades of Maltrin (M040, M100, and M150) were used to prepare binary powder mixtures (M040-M150 and M040-M100). For each mixture, magnesium stearate was added at concentrations of 0%, 0.16%, 0.32%, 0.48%, and 0.64%. The Hiestand Tableting Indices and other related mechanical properties were used to quantify the effects of magnesium stearate addition on the compaction properties of the binary mixtures. Linear relationships were observed between the Hiestand Bonding Indices and the compositions of the compacts in the absence of magnesium stearate. However, the Hiestand Bonding Indices were related to compact compositions in polynomial fashion when magnesium stearate was present in the binary mixtures. The Hiestand Brittle Fracture Indices varied with compact compositions in polynomial fashion with and without magnesium stearate.

The influence of magnesium stearate on the Hiestand Tableting Indices and other related mechanical properties of maltodextrins.

Magnesium stearate is widely used as a lubricant in pharmaceutical dosage forms. A film of magnesium stearate, or other lubricant, around individual granules is generally considered to cause the softening of tablets. Maltodextrins were chosen as model excipients since maltodextrins possessing a series of molecular weights showed systematically changing consolidation mechanisms. As maltodextrin molecular weight increases, the plasticity of the material increases. The Hiestand Tableting Indices and other related mechanical properties were used to study the effect of magnesium stearate addition on the mechanical properties and consolidation mechanisms of single component maltodextrins. Magnesium stearate was shown to lower the tensile strengths of maltodextrin compacts. Additionally, magnesium stearate addition lowered both the Hiestand Bonding Index and the Hiestand Brittle Fracture Index. The lower values of the Hiestand Brittle Fracture Index indicate that magnesium stearate promotes greater plastic behavior in maltodextrin compacts.