MAGNESIUM STEARATE QUALITY INDICATORS TO ESTIMATE ITS LUBRICATION PROPERTIES

Industrial manufacture of palleted medicinal preparations requires the use of excipients of various purposes among which magnesium stearate is of great importance giving lubrication properties to the tabletted substance. However, magnesium stearate has an unequal lubricating effect despite the fact that quality indicators of magnesium stearate from different manufacturers comply with the requirements of the Pharmacopoeia Monograph. In this work, a comparative analysis of magnesium stearate quality indicators from Merck KGaA (Germany) and Accent Microcell Pvt. Ltd. (India) was carried out. It was found that magnesium stearate from Merck KGaA (Germany) has the best lubrication properties having the smallest particle size and predominantly dihydrated form and characterized by the highest content of stearic acid. To identify hydrated forms of magnesium stearate thermal analysis was used making it possible to determine dehydration temperatures and melting of pseudopolymorphic structures by endothermic heat effects.