The Application Of Terahetrz Spectroscopy Technique In Medicine Analysis

THz (Terahertz) wave is generally defined as the frequency at0.1~10THzrange of electromagnetic wave, between the microwave and infrared in the electrospectrum. In this frequency range, material’s THz spectrum contains moleculeconfiguration and conformation, corresponding intermolecular vibration mode,phonon mode, and lattice vibrations, and much medicine have fingerprint peak interahertz range. In this paper, we have done determination of isomers medicine andvuidne medicine with THz-TDS, and obtained the fingerprint absorptioncharacteristic, and the spectrum can be used to do medicine types identification andcontents detection; Then, quantum chemistry calculate software is adopted tosimulate with single molecular mode and crystal mode; Finally, the regression modelof absorption coefficient and concentration is established to quantitative determinethe mixture drugs.The work finished in this paper is as the following:(1) Isomer is divided into two categories of the stereo-isomers and structuralisomers. In this paper, we have investigated the typical of chiral drugs and positionisomers of structural isomers. We have detected the chiral drugs fudosteine, naproxen,dihydroxybenzoic acid (DHBA) with its four position isomers, and obtained theirabsorption spectra. The results show that, left-handed (L)–fudosteine and racemic(DL)-fudosteine have fingerprint peaks, so the naproxen and their racemic body, aswell as the four isomers of DHBA. So this can be used to identification. Besides, wedetermined the fudosteine capsule, the absorption spectra of capsule is similar with(L)–fudosteine, but different with the (DL)–fudosteine.(2) The absorption spectra and refractive index spectra of four vudine drugs. Theexperiment show that, each drug has different frequency response. The result can beused as the basis of vudine drugs identified for established the drug moleculesfingerprint spectral database and provide experiment basis for moleculeconfiguration and conformation.(3) The theory simulation of single-molecule mode by Gaussian03and crystalmode by CRYSTAL09which is firstly used in medicine has been done. And we havefound that, the simulation with crystal structure is better than the single moleculemode. Moreover, we take the zidovudine for example, analyze the structure andfrequency. And finally found that the absorption peak of the material is mainlycaused by intermolecular and intramolecular vibration mode of joint action.(4) The absorption and refractive index spectroscopy of lamivudine andzidovudine in0.2-2.0THz have been firstly obtained with THz-TDS. The singlelinear and partial least squares regression model has been established to analyze the correlation between absorption coefficient and the concentration. The PLS model gotthe better prediction result, the correlation coefficient is0.9994, and the root meansquares error of calibration and validation are respectively.(5) We have done quantitative determination of mixed sample containingzidovudine and lamivudine in0.2-2.0THz range. We used the single linearregression mode and partial least squares mode to estimate the correlation absorptioncoefficient and concentration. The results show that the partial least squares modehad the better result, the precision is better than the result reported by currentedliterature. The correlation coefficients of the two contents with lamivudine,zidovudine, and nevirapine of non-linear model are respectively0.9994, and the rootmean squares errors of prediction are respectively1.0861%.