Effects of Magnesium Stearate on Tablet Properties

This experiment tested the influence of the lubricant magnesium stearate on the effectiveness of the drug acetaminophen in a mixture of glidants and excipients. There are many factors that can cause variation in the effectiveness of drugs in tablet form. Chief among them are the lubrication and glidant percentages, shear rate, tablet hardness and hydrophobicity. In order to allow the powder to flow through the tablet press without building up a static charge, glidant must be added and regulated in proper amounts to ensure that the hydrophobicity of the powder does not cause an undesirably long dissolution rate. Lubricant must be added to prevent the adhesion to and then the damaging of the Rotary Tablet Press. Too much lubricant, however, will cause the powder to form globules and to resist proper cohesion. This would fail to provide both full bioavailability and quick relief of symptoms. The effects of glidant/lubricant concentration were studied on the prior enumerated factors. The powders were mixed, blended to homogeneity, sheared, and compressed into tablets. Then the resulting tablets were tested for hydrophobicity, tablet hardness, tablet weight, and dissolution. It was found that including the glidant and lubricant was vital to counteract static and press adherence. However, the percentage of their concentrations must be kept at approximately 1% to avoid altering the powder and tablet properties as well as decreasing the dissolution rate. Following these guidelines, the tablets will maintain optimal hydrophobicity and percentage of drug release.