Kinetic approach had been undertaken to investigate the combined effect of pH and dielectric constant of the solvent on the stability of ascorbic acid in anaerobic condition. The decreased dielectric constant of solvent had marked stabilization effect on nonionized acid but had no significant effect on ionized ascorbic acid. The effect was very significant from dielectric constant 60 in propylene glycol-water system but was very significant at dielectric constant 70 in ethanol-water system. The decreased dielectric constant due to the addition of sorbitol in acidic solution also showed the similar stabilization. 利用動力學方法檢討pH及誘電常數對維生素丙在溶液中分解度的複合效應，發現溶媒的誘電常數降低對非解離型的維生素丙有顯著的安定作用，但對解離型之維生素丙少有意作用。亦即溶媒誘電常數之降低在酸性液中有顯著的維生素丙安定化作用。這種安定化作用之強弱和降低水溶液之誘電常數所添加的物質之種類有關，在pH3.2左右時，安定化作用強度順序為Sorbitol>Ethanol>Propylene glycol。根據此實驗結果，含有維生素丙之注射液及溶液，一般在酸性液中不安定性可利用適當的添加劑降低溶液之誘電常數，來增加其安定性。溶媒誘電常數之降低所引起之非解離型維生素丙之安定化作用，可能來自Polyol-Polyol間氫結合所形成之驟和系對加水分解之阻礙作用。
