The effect of magnesium stearate particle size on tablet properties and tableting characteristics of granules prepared with standard formulation

We investigated the effect of magnesium stearate particle size on the tablet properties and tableting characteristics of granules prepared with lactose/cornstarch in a 7/3 mixture and 3.5% binder of hydroxypropylcellulose as the standard formulation, as recommended by the Standard Formulation Research Association. Five grades of magnesium stearate produced from different sources of oil and fat (animal and vegetable sources) were used. They were used at concentrations of 0.25, 0.5 and 1%. The mixing times were 5, 10 and 40 min. It was found that when the median diameter of magnesium stearate was 10 μm or less, load transmissibility and ejection force during tableting, tablet hardness, and disintegration time changed markedly. More specifically, tablet properties and tableting characteristics were not only affected by the concentration and mixing time of the magnesium stearate, but were also closely related to particle size.