4种过期感冒药品的太赫兹光谱研究

针对近期几起过期药品致病的负面消息，为进一步提高药品质量检测的速度，提出采用太赫兹时域光谱技术（THz-TDS）无损检测药品质量的新方法。首先，通过飞秒激光器以及THz-TDS系统（Z-3）检测过期阿莫西林胶囊、复方氨酚烷胺片、板蓝根颗粒和复方板蓝根颗粒等常用感冒药的太赫兹时域光谱。然后，通过快速傅里叶变换（FFT），得到其太赫兹脉冲随频率变化的频谱图。接着，根据Dorney和Duvillaret等提出的THz-TDS提取光学参数模型，得到以上4种感冒药品的太赫兹特征吸收峰、吸收系数图谱和折射率。最后，将上述实验结果与相关文献报道的太赫兹特征吸收峰、吸收系数以及折射率进行对比。实验显示：过期阿莫西林胶囊和复方氨酚烷胺片在有效频段0.2~0.9 THz内的平均折射率分别为1.90和1.85，这比相关文献分别报道的最小折射率1.92和2.05小；过期板蓝根颗粒和复方板蓝根颗粒在有效频段0.2~1.4 THz内的平均折射率均为1.84，这较相关文献报道的最大折射率1.797略大；过期阿莫西林胶囊的5个太赫兹特征吸收峰均出现，但幅值有所降低；过期复方氨酚烷胺片的3个太赫兹特征吸收峰仍然存在，但幅值也有所降低，且在1.50 THz附近出现新的太赫兹特征吸收峰；过期板蓝根颗粒在1.43 THz出现新的太赫兹强特征吸收峰，且吸收系数减小；过期复方板蓝根颗粒在1.43，1.48和1.54 THz出现3个新的太赫兹特征吸收峰，且吸收系数也减小。结果表明：过期阿莫西林胶囊、复方氨酚烷胺片、板蓝根颗粒和复方板蓝根颗粒的有效成分均有所减少，部分化学成分已经发生改变；过期阿莫西林胶囊和复方氨酚烷胺片等西药的折射率会增大，而过期板蓝根颗粒和复方板蓝根颗粒等中药的折射率会减小；通过折射率的变化和太赫兹特征吸收峰位置的不同以及新出现的太赫兹特征吸收峰，可以区分以上4种过期药品，由此可以为太赫兹光谱技术区分过期药品提供参考。

Terahertz Spectroscopic Study for Expired Drugs

In response to the recent negative news of several expired drugs, in order to further improve the speed of drug testing, this paper proposes a new method for nondestructive testing of drug quality using terahertz time-domain spectroscopy (THz-TDS). Firstly, the terahertz time-domain spectra of expired amoxicillin capsules, compound paracetamol and amantadine hydrochloride tablets, Banlangen and compound Banlangen granules were tested by the Zomega THz-TDS system (Z3), and the femtosecond laser produced by Mai Tai. Secondly, through the Fast Fourier Transform (FFT), the frequency spectrum of sample was obtained. Thirdly, according to the THz-TDS extraction optical parameter model proposed by Dorney and Duvillaret et al., the four cold medicines’ spectrum of terahertz characteristic absorption peak, absorption coefficient and the refractive index were obtained. Finally, the experimental results were compared with the terahertz characteristic absorption peaks, absorption coefficients and refractive indexes reported in the related literatures. Experiments show that the average refractive indexes of expired amoxicillin capsules and compound paracetamol and amantadine hydrochloride tablets in the effective frequency range of 0.2~0.9 THz are 1.90 and 1.85, respectively, which is smaller than the minimum refractive index reported in the related literature of 1.92 and 2.05, respectively. The average refractive index of expired Banlangen granules and compound Banlangen granules in the effective frequency range of 0.2~1.4 THz was 1.84, which was slightly larger than the maximum refractive index reported in the related literature 1.797. The five THz characteristic absorption peaks of expired amoxicillin capsules all appeared, but the amplitudes decreased. The three THz characteristic absorption peaks of compound paracetamol and amantadine hydrochloride tablets still exist, but the amplitudes are reduced, and a new terahertz characteristic absorption peak appears near 1.50 THz. The expired Banlangen granules have a new terahertz characteristic absorption peak at 1.43 THz and the absorption coefficient is reduced. The expired compound Banlangen granules appear three new terahertz characteristic absorption peaks at 1.43, 1.48 and 1.54 THz, and the absorption coefficient is also reduced. The results showed that the effective components of expired amoxicillin capsules, compound paracetamol and amantadine hydrochloride tablets, Banlangen granules and compound Banlangen granules were reduced, and some chemical components had been changed. The refraction index of western medicines such as expired amoxicillin capsules and compound aminophenol tablets will increase, while that of expired Banlangen granules and compound Banlangen granules will decrease. The above four kinds of expired drugs can be distinguished by the change of the refractive index and their terahertz characteristic absorption peaks, which could provide a reference for distinguishing expired drugs with terahertz spectroscopy.