Purity and stability assessment of a semi-solid poly(ortho ester) used in drug delivery systems

Abstract

The purity and stability of a semi-solid poly(ortho ester) used in drug delivery systems is evaluated using a detailed analysis of the influence of the purification procedure and storage conditions. The bioerodible semi-solid POE was purified by a repeated purification procedure. Elimination of the small molecular weight oligomers and monomers and of the catalysts and stabilizers used in the synthesis, as well as a decrease of the polydispersity, were obtained with this method. Fourier transform infrared analysis also verified the disappearance of degradation products after the first precipitation.