THE EFFECT OF THE VARIABILITY IN THE PHYSICAL AND CHEMICAL PROPERTIES OF MAGNESIUM STEARATE ON THE PREPARATION OF COMPRESSED TABLETS (RAW MATERIALS, VARIATION, LUBRICANTS)
Abstract
A series of magnesium stearate samples, supplied by foreign and domestic manufacturers, were characterized by their physical and chemical properties. The results indicated that the samples differed, significantly, with respect to chemical purity, crystal structure, particle size, and surface area. The properties of magnesium stearate lots, manufactured by the same company, were very similar. Whatever variation that was seen was principally due to different suppliers. The studies that were conducted indicated that magnesium stearate source variation affected the bulk volume of microcrystalline cellulose and the flow rates of dicalcium phosphate, and tricalcium phosphate when mixed with various magnesium stearate samples. Several directly compressible tablet formulations were prepared and evaluated, using samples of magnesium stearate obtained from 16 sources. Differences in tablet quality were observed in regard to tablet hardness, friability, disintegration, and dissolution. The data showed that the smaller particle size magnesium stearates (2.4-7.0 um), with a large surface area, (10.6-14.8 m('2)/g) had the most detrimental effect on the physical properties of the compressed tablets. The finer particle sized stearates disrupt a greater number of excipient bonding sites, resulting in weaker tablets. The magnesium stearate samples with greater surface areas form a more extensive hydrophobic tablet matrix, which prolongs tablet disintegration and dissolution rates. Regression analysis and modeling was used to define, quantitate, and predict the effect of magnesium stearate source variation on the physical properties of several tablet formulations. The results from the study indicate that the models developed could predict tablet hardness, disintegration, and dissolution with a satisfactory degree of assurance.
Degree
Ph.D.
Subject Area
Pharmaceuticals
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