Poly(maleic acid-co-propane-1,2-diol-co-adipic acid) for pH-triggered drug delivery

Poly(maleic acid-co-propane-1,2-diol-co-adipic acid) was synthesized using xylene as the reaction medium in Dean-Stark apparatus. The synthesized co-polyester was characterized by its FTIR-spectrum, elemental analysis, molecular weights, solubility in common organic solvents and hydrolytic degradation test. From the hydrolytic degradation study it was found that the polyester sample remained almost intact in the acid medium but gradually degraded in basic medium. Because of such pH-responsive degradation nature, this polyester was tried as an enteric coating material for non-steroidal anti-inflammatory drugs. Drug release from the polymer coated specimen in simulated physiological environments was investigated and British Pharmacopoeia standard enteric coating properties of the polymer were observed.