This proposal is concerned with the synthesis of new macromolecules for uses in medicine and biochemical research. Specifically, a new class of polymers, known as polyphosphazenes, will be explored both as biologically stable, water-insoluble materials for artificial organ or membrane research or as substrates for affinity chromatography or immobilized enzymes or cells, and as water-soluable or biodegradable polymers for controlled-release drug delivery. The program is divided into two parts; first, a fundamental study of syntheses, reaction mechanisms, and hydrolysis pathways of small-molecule cyclic phosphazenes used as models, and second, a utilization of the fundamental information for the synthesis of the more challenging macromolecular systems. The testing of these compounds will be accomplished through collaborative programs with other research groups.