DEGRADATION OF POLY(BETA-MALIC ACID) - MONITORING OF OLIGOMERS FORMATION BY AQUEOUS SEC AND HPCE

Poly(beta-malic acid) is a functional aliphatic polyester which can serve as parent compound to make systems aimed at temporary therapeutic applications. Degradation of the polyester backbone of poly(beta-malic acid) leads to the formation of oligomers which can be hardly separated by conventional Size Exclusion Chromatography. In order to monitor the formation of oligomeric degradation by-products and to quantify their relative amount, the potential of two separation techniques has been investigated, namely Aqueous Size Exclusion Chromatography using a Bio-Gel P2 gel column and High Performance Capillary Electrophoresis. Aqueous SEC allowed separation of oligomers smaller than hexamer whereas HPCE successfully separated oligomers smaller than pentadecamers. These techniques were used to control the efficiency of oligomer fractionation by the dissolution/precipitation method applied to the sodium salt of poly(beta-malic acid).