Stabilization of 5-aminolevulinic acid by the zinc(II) ion in an aqueous solution

It is known that 5-aminolevulinic acid (5-ALA) is not stable in an aqueous solution because of the auto-condensation reaction between two 5-ALA molecules; however, in this study, 5-ALA was stabilized by the zinc(II) ion in an aqueous solution of neutral pH. This stabilization effect was ascertained by UV-Vis Spectroscopy and 1H and 13C NMR Spectroscopy.