SYNTHESIS AND CHARACTERIZATION OF A NEW FAMILY OF POLY(ORTHO ESTER)S

A previously reported synthesis of ointment-like poly(ortho ester)s prepared from a flexible triol and an alkyl orthoacetate has been extended to the preparation of solid materials by replacing the flexible triol with a rigid triol. The hydrolysis products of the polymer have been determined, and the hydrolysis has been shown to proceed exclusively by cleavage of the exocyclic alkoxy group of the ortho ester linkage. The lowest alkyl analog is crystalline, but the higher alkyl analogs are amorphous. The polymer is hydrolytically labile, and the rate of hydrolysis increases as the pH of the erosion medium decreases.