Decomposition of aspirin in the solid state in the presence of limited amounts of moisture III: Effect of temperature and a possible mechanism.

In a previous study, we showed that aspirin in the presence of limited amounts of moisture falls to follow Leeson-Mattocks kinetics at 62.5 degrees C. This system has been tested at a series of temperatures, and several plausible models have been tested. It is shown that the data are explained by a model in which the reaction is limited to a surface interaction between aspirin and water from the sorbed bulk moisture layer.