Synthesis of poly(orgnaophosphazenes) with glycolic acid ester and lactic acid ester side groups: prototypes for new bioerodible polymers

Poly[bis-(ethylglycolato)phosphazene], poly[bis(ethyl lactato)phosphazene], poly[bi(benzylglycolato)phosphazene], and poly[bis(benzyl lactato)phosphazene] were synthesized. The benzyl esters of glycolic and lactic acid were prepared by the base-catalyzed transterification of their ethyl esters with benzyl alcohol at 90°C. Poly(dichlorophosphazene) was treated with a large excess of the appropriate sodium acid ester at 50°C to yield the fully-substituted polymer. The hydrolytic decomposition profiles of these polymers in aqueous media were monitored by NMR