在这项工作中,报道了在碱性水溶液存在下褪黑激素(MEL)水解和MEL光降解的补充紫外可见(UV-VIS)光谱和光致发光(PL)研究。MEL的UV-VIS光谱的特征在于在278nm处具有峰值的吸收带。在NaOH溶液存在下,该峰移至272nm,同时在329nm处的能带吸光度增加。位于308nm处的等吸光点表明除了MEL和NaOH之外还产生了一些化合物。MELPL光谱的特征在于365nm处的带。随着在药物溶液中添加的碱性溶液浓度的增加,MELPL强度逐渐降低。在MEL样品与碱性溶液相互作用的情况下,当暴露于UV光的时间达到310分钟时,在335nm处出现新的光致发光激发(PLE)带。MELPLE波段的下移,从321到311纳米,由于赋形剂的存在,也显示了。参考MEL水解产物解释这些变化。
In this work, a complementary ultraviolet-visible (UV-VIS) spectroscopy and
photoluminescence (PL) study on melatonin (MEL) hydrolysis in the presence of alkaline aqueous solutions and the photodegradation of MEL is reported. The UV-VIS spectrum of MEL is characterized by an absorption band with a peak at 278 nm. This peak shifts to 272 nm simultaneously with an increase in the band absorbance at 329 nm in the presence of an NaOH solution. The isosbestic point localized at 308 nm indicates the generation of some chemical compounds in addition to MEL and NaOH. The MEL PL spectrum is characterized by a band at 365 nm. There is a gradual decrease in the MEL PL intensity as the alkaline solution concentration added at the drug solution is increased. In the
case of the MEL samples interacting with an alkaline solution, a new
photoluminescence excitation (PLE) band at 335 nm appears when the exposure time to UV light reaches 310 min. A down-shift in the MEL PLE band, from 321 to 311 nm, as a consequence of the presence of excipients, is also shown. These changes are explained in reference to the MEL hydrolytic products.