Solid-state decomposition of alkoxyfuroic acids in the presence of microcrystalline cellulose.

A solid-solid interaction between alkoxyfuroic acids and microcrystalline cellulose has been studied. The decomposition of the mixture differs from that of the drug(s) alone, in that carbon monoxide (not carbon dioxide) is the high-temperature decomposition product. A model is proposed in which interaction occurs at contact points. A liquid decomposition product, dissolving part of the alkoxyfuroic acid (to the extent of its solubility) serves as a carrier, so that the number of contact points increases, thus accelerating the reaction. Both the main and ancillary parameters have calculated values that are consistent with the model.