電荷移動を利用する医薬品化合物の分解抑制 その2 : メチル置換ベンゼン誘導体によるRiboflavine Tetrabutyrateの光分解抑制とその機構

抄録

Studies were made, in ethylene dichloride, on inhibition by methylsubstituted benzene derivatives of the photodecomposition of riboflavine tetrabutyrate and also on the interaction between substituted benzenes and the riboflavine derivative. The photodecomposition of riboflavine tetrabutyrate was inhibited by the presence of benzene derivatives having three or more substituted methyl groups; the inhibitory effects decreased in the order of hexamethylbenzene>pentamethylbenzene>1, 2, 4, 5-tetramethylbenzene>1, 2, 4-trimethylbenzene. Examinations were made on the fluorescence quenching of riboflavine tetrabutyrate by the substituted benzenes and on the new absorption bands which appeared in the vicinity of 485-490 mμ of difference spectra of the interaction systems : it was found that complexes of 1 : 1 molar ratio were formed. Analysis of solvent effects on the interaction indicated that, at the excited state, dynamic quenching mechanism was also participating. From the correspondence of the inhibition and the interaction data, it was concluded that charge-transfer force is responsible for the inhibition of photodecomposition of riboflavine tetrabutyrate by the substituted benzenes.