Synthesis, degradation, and drug delivery of cycloaliphatic poly(ester anhydride)s

The high melting point of poly(1,4-cyclohexanedicarboxylic anhydride) [poly(CHDA)] is a disadvantage, in that it is intractable in the melting process of a drug delivery system. This report relates to diols introduced into the polyanhydride main chain to decrease its melting point. Various poly(ester anhydride)s containing ethylene glycol, 1,3-propanediol, 1,4-butanediol, or 1,6-hexandiol [poly-(CHDA-XDO)] were synthesized by the esterification reaction and melt polycondensation. FTIR, DSC, WAXD, and intrinsic viscosity of polymers were recorded and hydrolytic degradation, as well as in vitro drug delivery, was conducted. The results show that the samples are stable in an anhydrous environment at room temperature and degrade in water following a surface erosion mechanism. The degradation period of poly(CHDA-XDO) ranged from 130 to 320 h as a result of the different diols and amounts of XDO introduced. The in vitro drug delivery gave 130-350 h of stable delivery along with the typical surface erosion mechanism.