Direct photodegradation of lamotrigine (an antiepileptic) in simulated sunlight--pH influenced rates and products.
Direct photodegradation of lamotrigine (an antiepileptic) in simulated sunlight--pH influenced rates and products.
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拉莫三嗪（一种抗癫痫药）在模拟阳光下的直接光降解——pH 值影响速率和产物。
DOI：
10.1039/c3em00581j
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
T. Borch
中科院分区：
文献类型：
--
作者：
Robert B. Young;B. Chefetz;Aiju Liu;Y. Desyaterik;T. Borch
拉莫三嗪是一种抗癫痫和情绪稳定药物，已在废水，地下水，地表水和饮用水中检测到，地表水中的频率范围为47%至97%。由于拉莫三嗪是一种弱碱（pKa = 5.7），在天然沃茨中以两种质子化状态出现，因此本研究采用液相色谱-紫外二极管阵列检测器和pH 3.3、5.3和7.7的缓冲水溶液，在模拟日光中检测拉莫三嗪（11.4至12.0 mg L（-1））的直接光降解。拉莫三嗪的半衰期随溶液pH值的变化很小（100 ± 3至112 ± 2 h），但其比光吸收率高12倍，反应量子产率低13倍，在pH 7.7与pH 3.3。在美国科罗拉多州丹佛市（纬度39.8617 °N）估计的正午、仲夏阳光下，拉莫三嗪在pH 7.7下的估计光降解速率是pH 3.3下的两倍多。采用液相色谱-紫外二极管阵列检测器和飞行时间质谱检测拉莫三嗪的光产物。溶液的pH值被证明会影响拉莫三嗪的光产物的身份和相对丰度。一些光产物只出现在含有质子化拉莫三嗪的溶液中，而另一些光产物只出现在含有中性拉莫三嗪的溶液中。因此，提出了不同的反应机理。最后，拉莫三嗪的反应量子产率（2.51 ± 0.07 × 10（-5）mol einstein（-1），pH 7.7）和其他结果表明，拉莫三嗪和三种光产物对直接光降解的抗性与卡马西平（一种在表面沃茨中经常检测到的药物）大致相同。
Lamotrigine is an antiepileptic and mood stabilizing drug that has been detected in wastewater, groundwater, surface water and drinking water, at frequencies in surface water ranging from 47 to 97%. Because lamotrigine is a weak base (pKa = 5.7) that appears in two protonation states in natural waters, this study examined the direct photodegradation of lamotrigine (11.4 to 12.0 mg L(-1)) in simulated sunlight using liquid chromatography-UV diode array detection and buffered aqueous solutions at pH 3.3, 5.3, and 7.7. Lamotrigine's half-life varied little (100 ± 3 to 112 ± 2 h) with solution pH, but its specific light absorption rate was 12 times higher, and its reaction quantum yield was 13 times lower, at pH 7.7 versus pH 3.3. In the estimated midday, midsummer sunlight in Denver, CO, USA (latitude 39.8617 °N), lamotrigine's estimated photodegradation rate was more than twice as fast at pH 7.7 versus pH 3.3. Lamotrigine's photoproducts were detected by liquid chromatography-UV diode array detection and time-of-flight mass spectrometry. Solution pH was shown to affect the identities and relative abundances of lamotrigine's photoproducts. Some photoproducts appeared only in solutions containing protonated lamotrigine, and others appeared only in solutions containing neutral lamotrigine. As a result, different reaction mechanisms were proposed. Finally, lamotrigine's reaction quantum yield (2.51 ± 0.07 × 10(-5) mol einstein(-1) at pH 7.7) and other results suggested that lamotrigine and three photoproducts are approximately as resistant to direct photodegradation as carbamazepine, a frequently detected pharmaceutical in surface waters.
影响因子：
1.8
作者：
U. Schneider;Yiyong Huang;A. Chakrabarti;H. T. Dao;N. Morita;S. Kobayashi
通讯作者：
U. Schneider;Yiyong Huang;A. Chakrabarti;H. T. Dao;N. Morita;S. Kobayashi