Photo-Stabilization and Solubilization of an Aldose Reductase Inhibitor, (E) -3-Carboxymethyl-5- [(2E) -methyl-3-phenylpropenylidene] rhodanine (ONO-2235), by Human Serum Albumin

Abstract

Photo-stabilization and solubilization of an aldose reductase inhibitor, (E) -3-carboxymethyl-5- [(2E) -methyl-3-phenylpropenylidene] rhodanine (ONO-2235), by human serum albumin (HSA) were investigated in aqueous solution. ONO-2235 dissolved in pH 7.4 phosphate buffer was photostabilized by a factor of about 150 in the presence of a 5-fold excess of HSA per mole of the drug. The solubilities of ONO-2235 in the buffer and distilled water were increased about 17-fold and 57-fold, respectively, by the presence of 6 ×10^-4 M or more HSA. The binding parameters for the interaction between ONO-2235 and HSA were determined from equilibrium dialysis data. These results indicate the usefulness of HSA as a drug additive.