Studies on the syntheses and drug release properties of polyanhydrides containing phosphonoformic (or acetic) acid ethyl ester in the main chain

Polyanhydrides were synthesized by melt polymerization of bis(p-carboxyphenyloxy ethoxy), phosphonoformic(or acetic) acid ethyl ester 1(or 2). Copolyanhydrides were similarly prepared from (or 2) and bis(p-carboxyphenoxy)propane (CPP), or sebacic acid (SA). The chemical structures of these new polyanhydrides and copolyanhydrides were confirmed by ¹H NMR, FTIR and elemental analysis. The average molecular weight of these polymers was investigated. In vitro degradation of polyanhydrides and copolyandhydrides in phosphate buffer solution at 37°C was monitored by HPLC. Experimental data revealed that fission of phosphate bond took place after that of the anhydride bond. Enzymatic degradation showed that Ribonuclease could catalyze and accelerate the degradation of these polyanhydrides. Drug release profile of antitumor agents MTX and 5-Fu were also studied.