Identification of small molecules formed from polymethyl glyoxylate degradation in vitro

The ultimate degradation of poly(methyl glyoxylate) (PMG) leads to glyoxylic acid which is a metabolite. Nevertheless, in a confined medium, various equilibria can occur between ester, acid, hemiacetal and acetal functions and a priori different molecules can be formed. Thus, whatever the application expected for this polymer and particularly in the case of pharmaceutical applications, it is of the first importance to know the compounds able to be released during its degradation. In this work, hydrolysis of small model molecules was followed by using H-1 NMR to understand the hydrolytic mechanism of this type of molecule. Consequently, the degradation of PMG in a confined aqueous medium is elucidated and, among the considered molecules, four are finally detected in water: methyl glyoxylate hydrate (HMG), 2-hydroxy-2-methoxy-methylacetate (HMMA) and, as main products, glyoxylic acid hydrate (HGA) and 2-hydroxy-2-methoxy-acetic acid (HMAA). (C) 1999 Elsevier Science Ltd. All rights reserved.