THE HYDROLYSIS AND EXCRETION OF POLYMERIC PHOSPHATE

¹ Division of Pharmacology, Department of Radiation Biology, University of Rochester School of Medicine and Dentistry, Rochester, N. Y.

Two linear phosphate polymers were extensively hydrolyzed to orthophosphate in rats and rabbits. In contrast two cyclic polymers suffered almost no hydrolysis and were promptly recovered as intact molecules in the urine.

Studies on linear or open-chain compounds showed that tripolyphosphate was more rapidly and more extensively degraded in vivo than its homologue with six atoms of phosphorus (labelled hexametaphosphate). The dose, route of administration, and associated cation all influenced the extent to which unhydrolyzed polymer escaped in the urine. Sodium salts of tripolyphosphate and hexametaphosphate were more rapidly mobilized from sites of injection and provided larger amounts of polymeric phosphate in the urine than did the corresponding calcium salts.

Although the cyclic polymers trimeta- and tetrametaphosphate were excreted virtually unchanged after parenteral administration, a small fraction of injected trimetaphosphate was converted to orthophosphate in rats and rabbits. All four polymers appeared to be hydrolyzed when given by the oral route.

Tissue sites of these enzymatic hydrolyses were not identified; no activity was present in blood or urine.

This article has been cited by other articles:

				J. M. Navia and R. S. Harris Longitudinal Study of Cariostatic Effects of Sodium Trimetaphosphate and Sodium Fluoride When Fed Separately and Together in Diets of Rats Journal of Dental Research, March 1, 1969; 48(2): 183 - 191. [PDF]