T. Miller, P. York
1985
Citations
1
Influential Citations
44
Citations
Journal
International Journal of Pharmaceutics
Abstract
Abstract High purity magnesium stearate and palmitate powders have been prepared at two batch sizes under different pH environments. Larger batch products were analyzed for chemical and physical character using gas chromatography, atomic absorption, surface area estimation, scanning electron microscopy, thermal analysis (moisture evolution analysis, DSC, TGA, hot stage microscopy), infra-red and X-ray diffraction techniques. Powder particles produced under acid conditions had a thin, regular, plate-like appearance whilst those manufactured from alkaline conditions had more irregular structure. Acid-manufactured powders were found to be associated with two molecules of water and had a small degree of structure which was disrupted on drying. Materials precipitated from alkaline conditions appeared to consist of two species, the major one being one molecule of magnesium stearate or palmitate associated with two molecules of water and the second minor component probably associated with equimolar proportions of water. Estimates of activation energy (Ea) associated with the major thermal transitions confirmed the low level molecular structure in prepared materials.