M. Lamson, J. Fox, W. Higuchi
Sep 1, 1984
Citations
0
Influential Citations
32
Citations
Journal
International Journal of Pharmaceutics
Abstract
Abstract 1-Hydroxyethylidene-1,1-bisphosphonic acid (HEDP) is used in a variety of diagnostic, research and therapeutic applications at in vivo concentrations of from 1 mM. Previous studies have shown that calcium and HEDP form polynuclear aggregate complexes at high pH. Calcium ion titrations at constant pH 8.0, and pH titrations at 1:1 and 2:1 ratios of total calcium to total diphosphonate, provide evidence for the occurrence of aggregation of calcium and HEDP under physiological conditions. A robust feature of several polynuclear models examined is a dramatic pH dependence of polynuclear species concentrations between pH 5.5 and 7.0.