RESUMO
Objective:To research the correlation between the cobamamide photodegradation products in the visible light area at different wavelengths and the photodegradation rate intensity. Methods:The 40-minute illumination experiment was conducted for co-bamamide reference solution respectively at the wavelength of 400 nm,450 nm,500 nm,550 nm,600 nm,650 nm and 700 nm under the illumination of 50 Lx,100 Lx,200 Lx,300 Lx,400 Lx and 500 Lx,respectively. An HPLC method was used to detect the cobam-amide content after the irradiation, the contents and proportions of hydroxocobalamin and adenosine (two photodegradation products) were calculated and the two photodegradation products were confirmed by mass spectrum. Results:The main photodegradation products of cobamamide (impurity 1,adenosine and hydroxocobalamin) had the similar photodegradation tendency. Within the scope of 50 Lx-200 Lx,the illumination intensity affected the concentration ratio of hydroxocobalamin and adenosine obviously. Within the scope of 200 Lx-500 Lx,the illumination intensity showed smaller effect. Under the different wavelengths and photodegradation rate intensity, the content of hydroxocobalamin was higher than that of adenosine under the same experimental condition.Conclusion:This paper re-searched the cobamamide photodegradation products in the optimum dark condition. The method is accurate and reliable,which can be used for the control of photodegradation related substances of cobamamide.