Abstract
Vitamin K2 (K2) syrup has begun to be administered to newborn for prophylaxis of intracranial hemorrhage due to vitamin K deficiency. The stability of K2 syrup (2mg/ml) and its diluted solution (0.2mg/ml) in a plastic bottle with or without an orange bag to exclude light was examined by micro high pressure liquid chromatography.
When light was excluded by the orange bag, regardless of a color of bottle, the concentration of K2 and storage temperature, the residual rate of K2 in an ophthalmic bottle (10ml) was more than 90% after 1 month under a fluorescent light (500 lux) shed for 10-12 hours per day. But when light was not excluded by the orange bag, K2 decomposed to less than 40% and was somewhat more stable in a brown-colored bottle than in a colorless bottle, and in syrup than in its diluted solution. K2 in a dispensing bottle (30ml) without a light-resistant cover decomposed to 76-85% in only 9 hours under fluorescent light.
Therefore, K2 syrup and its diluted solution should be administered in light-excluding containers. Photodegradation of K2 in the plastic bottle was inhibited when stored in an orange bag.
