In Vitro Study on Combined Effect of Drugs for Hyperphosphatemia on Phosphorus Adsorption Capacity.

Phosphorus binders are often used in combination to produce synergistic effects. However, the synergistic effect may be affected by the change in pH or concomitant drugs. Nonetheless, the data on the adsorption capacities of these binders when used in combination with other binders are limited. In this study, we evaluated the adsorption capacity of phosphorus binders when used in combination. Precipitated calcium carbonate (CC), ferric citrate hydrate (FC), lanthanum carbonate hydrate (LC), and sucroferric oxyhydroxide (SO) were used as phosphorus binders. SO showed high adsorption capacity in the 1st and 2nd fluid, and the adsorption capacity of SO in combination with other binders was stable. In contrast, the adsorption capacities of CC + FC and FC + LC decreased in the 1st and 2nd fluid compared with that when used alone because of the release of citrate ions that chelate calcium or lanthanum ions. These results suggest that SO is less affected by interactions with other phosphorus binders and changes in pH and may be suitable for patients receiving concomitant drugs.