Evaluation of sodium stearyl fumarate as a tablet lubricant

Abstract

The ability of sodium stearyl fumarate to reduce friction and adhesion to the punches was investigated as well as its influence on the tablet strength and the disintegration time. The effect of lubricant concentration, particle size and the mixing time was investigated using lactose and sodium chloride as tablet materials. A direct comparison with magnesium stearate in 6 tablet formulations was also made. The friction during compression and ejection of the tablets was measured in an instrumented tablet machine. Sodium stearyl fumarate reduced the friction and the adhesion to about the same degree as magnesium stearate and had also about the same influence on tablet strength and disintegration. The particle size of sodium stearyl fumarate was of great importance and all effects correlated better to the surface area than to the weight fraction. Prolonged mixing improved its lubricating effect and had no effect on the disintegration but reduced the strength of sodium chloride tablets. Sodium stearyl fumarate appears to be a good alternative to magnesium stearate.