Ho P C, Wong V K
Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
PDA J Pharm Sci Technol. 1998 May-Jun;52(3):129-33.
On exposure to UV light at 254 nm in a borosilicate glass actinometer, vitamin k1 decomposed rapidly with a degradation rate constant of 7.63 day-1. Under UV irradiation, DL methionine and sodium metabisulphite were found to have some photostabilizing effect for vitamin k1 formulations. The degradation rates were reduced by 43.4% and 60.4% in the presence of 0.1% w/v of DL methionine and 0.2% w/v of sodium metabisuphite, respectively. When vitamin k1 formulations were stored at room temperature in clear glass bottles and exposed to the weaker light source of both room fluorescent light and natural daylight, vitamin k1 decomposed at a much slower degradation rate constant of 0.31 day-1. Despite the slower degradation rate, DL methionine and sodium metabisuphite failed to protect vitamin k1 from degradation on exposure to this weaker light source. When vitamin k1 was stored in white plastic bottles under the same testing conditions, the photo-protective effect of these photostabilizers reappeared. The protection provided extended the shelf-life from one day to 2.5 days. When amber glass bottles replaced white plastic bottles as storage containers, vitamin k1 was found stable on an open bench for at least 30 days. Such stability was also observed when vitamin k1 was stored in a refrigerator in either white plastic bottles or amber bottles. Findings in this study showed that package and storage conditions that shield the products from light are still the most efficient ways to maintain the photostability of vitamin k1. However, photostabilizers such as DL methionine and sodium metabisulphite may provide additional protection to vitamin k1 when it is stored in less effective light-resistant containers.
在硼硅酸盐玻璃化学光度计中于254 nm紫外光照射下，维生素K1迅速分解，降解速率常数为7.63天-1。在紫外光照射下，发现DL-蛋氨酸和焦亚硫酸钠对维生素K1制剂有一定的光稳定作用。在存在0.1% w/v的DL-蛋氨酸和0.2% w/v的焦亚硫酸钠时，降解速率分别降低了43.4%和60.4%。当维生素K1制剂在透明玻璃瓶中于室温下储存并暴露于室内荧光灯和自然日光这两种较弱光源时，维生素K1以0.31天-1的慢得多的降解速率常数分解。尽管降解速率较慢，但DL-蛋氨酸和焦亚硫酸钠在暴露于这种较弱光源时未能保护维生素K1免于降解。当维生素K1在相同测试条件下储存在白色塑料瓶中时，这些光稳定剂的光保护作用再次出现。所提供的保护将保质期从一天延长至2.5天。当用琥珀色玻璃瓶代替白色塑料瓶作为储存容器时，发现维生素K1在开放式工作台上至少30天稳定。当维生素K1储存在白色塑料瓶或琥珀色瓶中的冰箱中时也观察到了这种稳定性。本研究的结果表明，使产品避光的包装和储存条件仍然是维持维生素K1光稳定性的最有效方法。然而，当维生素K1储存在防光效果较差的容器中时，DL-蛋氨酸和焦亚硫酸钠等光稳定剂可能会为维生素K1提供额外的保护。
