Improvement of the Photostability of Phytonadione (Vitamin K₁) in Model Infusion Fluids

Effect of Addition of Fat-soluble Vitamin on the Photodegradation of Phytonadione

Abstract

One of three fat-soluble vitamins, tocopherol, ubidecarenone, and retinol palmitate was added to improve the photostability of vitamin K₁ (K₁) in model infusion fluids. The time courses of photodegradation of K₁ and the vitamin added in infusion fluid under the irradiation of monochromatic light or fluorescent lamp were followed by using high-performance liquid chromatographic method. K₁ and retinol palmitate in infusion fluid were more photolabile within the wavelength range of 300-400 nm, while tocopherol and ubidecarenone were stable at wavelengths above 320 nm. The photolytic degradation of K₁ was inhibited most effectively by the addition of ubidecarenone, whereas no satisfactory inhibition effect was obtained for tocopherol. The degradation rate constant of K₁ decreased remarkably with the increase in amount of ubidecarenone added. The photostabilizing effect was thus closely related to the photostability and light absorption properties of the vitamins added.