THz Spectral Database for Pharmaceuticals
                              Last Update: May. 25, 2026, Shizuoka University, Japan


Spectra without watermark
    We can provide Spectra without watermark.
    Please contact sasaki.tetsuo + @ + shizuoka.ac.jp .

Sample preparation procedure for THz spectroscopy
    Each sample powder of API (pharmaceutical, medicine, drug) was used without any recrystallization or further purification process after purchase.
    (except for the sample written as "recrystalization")
    They were milled to reduce its particle size small enough to prevent scattering.
    Then they were diluted with polyethylene (PE) powder having a mean particle diameter of 20 μm.
    At last, they were pressed into 1 to 2 mm thick pellets (20 mm diameter) under a pressure of 2000 kg.

* Sample preparation procedure 2 for THz spectroscopy
    For * marked sample, sample powder of API (pharmaceutical, medicine, drug) was directly pressed into 100 μm thick plates (7 mm diameter) after milling the sample.
** Sample preparation procedure 3 for THz spectroscopy
     ** marked sample is wafer/plate of its material.
Active Pharmaceutical Ingredients (API)
     Measured by THz spectrometer 1
     Each spectrum was normalized using the spectrum without sample. (= each spectrum always includes PE absorption)
     Temperature dependence spectra were measured in vaccuum, from low to high temperature.
     Also, XRD spectrum of each sample is presented.
 Active Pharmaceutical Ingredients 2 (API 2)
     Measured by THz spectrometer 2
     Each spectrum was normalized using the spectrum of a reference pellet made of pure PE.
     Spectra were obtained in dry air at room temperature.
     Also, XRD spectrum of each sample is presented.
 Additives 1
     Measured by THz spectrometer 1
     Each spectrum was normalized using the spectrum without sample. (= each spectrum always includes PE absorption)
     Temperature dependence spectra were measured in vaccuum, from low to high temperature.
     Also, XRD spectrum of each sample is presented.
 Additives 2
     Mainly measured by THz spectrometer 2
     Each spectrum was normalized using the spectrum of a reference pellet made of pure PE.
     Spectra were obtained in dry air at room temperature.
 Amino acids 1
     Measured by THz spectrometer 1
     Each spectrum was normalized using the spectrum without sample. (= each spectrum always includes PE absorption)
     Temperature dependence spectra were measured in vaccuum, from low to high temperature.
     Also, XRD spectrum of each sample is presented.
 Amino acids 2
     Measured by THz spectrometer 2
     Each spectrum was normalized using the spectrum of a reference pellet made of pure PE.
     Spectra were obtained in dry air at room temperature.
 DNA components 1
     Measured by THz spectrometer 1
     Each spectrum was normalized using the spectrum without sample. (= each spectrum always includes PE absorption)
     Temperature dependence spectra were measured in vaccuum, from low to high temperature.
     Also, XRD spectrum of each sample is presented.
 DNA components 2
     Measured by THz spectrometer 2
     Each spectrum was normalized using the spectrum of a reference pellet made of pure PE.
     Spectra were obtained in dry air at room temperature.
 Sugars
     Measured by THz spectrometer 2
     Each spectrum was normalized using the spectrum of a reference pellet made of pure PE.
     Spectra were obtained in dry air at room temperature.
 Vitamins 1
     Measured by THz spectrometer 1
     Each spectrum was normalized using the spectrum without sample. (= each spectrum always includes PE absorption)
     Temperature dependence spectra were measured in vaccuum, from low to high temperature.
     Also, XRD spectrum of each sample is presented.
 Vitamins 2
     Measured by THz spectrometer 2
     Each spectrum was normalized using the spectrum of a reference pellet made of pure PE.
     Spectra were obtained in dry air at room temperature.
 Recrystallization 1
     Mainly measured by THz spectrometer 1
     Each spectrum was normalized using the spectrum without sample. (including PE absorption)
     Temperature dependence spectra were measured in vaccuum.
     Also, XRD spectrum of each sample is presented.
Recrystallization 2
     Measured by THz spectrometer 2
     Each spectrum was normalized using the spectrum of a reference pellet made of pure PE.
     Spectra were obtained in dry air at room temperature.
 Other materials
     Mainly measured by THz spectrometer 1
     Each spectrum was normalized using the spectrum without sample. (including PE absorption)
     Temperature dependence spectra were measured in vaccuum.
     Also, XRD spectrum of each sample is presented.
Other materials 2
     Measured by THz spectrometer 2
     Each spectrum was normalized using the spectrum of a reference pellet made of pure PE.
     For ** samples, each spectrum was normalized using the spectrum without sample.
     Spectra were obtained in dry air at room temperature.


→Transmittance



THz spectrometer 1: CW-type (High resolution)
    CW GaP THz Signal Generator (THz-SG) is utilized as light source of the spectrometer.
    Pump beams of THz-SG are semiconductor lasers with Fiber Amplifier.
    Frequency range: 0.5 - 6.0 THz.
    Frequency accuracy: 3 MHz.
    Frequency resolution: ~ 8MHz.

     [ref 1] Tetsuo Sasaki, Tadao Tanabe, and Jun-ichi Nishizawa,
       "Frequency stabilized GaP continuous-wave terahertz signal generator for high-resolution spectroscopy",
        Optics and Photonics Journal, 2014, 4, 8-13.
     [ref 2] Tetsuo Sasaki, Tadao Tanabe, and Jun-ichi Nishizawa,
       "Development of Continuous Wave Terahertz Signal Generator based on Difference Frequency Generation in Gallium Phosphide Crystal",
        J. Jpn. Soc. Infrared Science & Technology, Vol.26 No.1　(2016.8) pp.74-81.
     [ref 3] Tetsuo Sasaki, Tadao Tanabe, and Jun-ichi Nishizawa,
       "Frequency Resolution and Accuracy Improvement of a GaP CW THz Spectrometer",
        Recent Global Research and Education: Technological Challenges, Advances in Intelligent Systems and Computing 519, 2017 p.33-38.
        Springer International Publishing, Edited by R. Jablonski and R. Szewczyk, DOI 10.1007/978-3-319-46490-9_5.

THz spectrometer 2: nano second pulse type
    Pump beams of THz-SG are two Cr:Forsterite lasers.
    Frequency Range: 0.5 - 6.1 THz.
    Frequency accuracy & resolution: 15 GHz.

     [ref] Ken Suto, Tetsuo Sasaki, Tadao Tanabe, Kyosuke Saito, Jun-ichi Nishizawa and Masahiko Ito,
        "GaP THz-wave generator and THz spectrometer using Cr:Forsterite lasers",
         Rev. Sci. Instruments 76, 123109 (2005).

XRD measurement
    RINT2200 (Rigaku, Japan)
    X-ray source: Cu-Kα, 40 kV.
    Range: 5 - 35 deg.
    Sampling width: 0.02 deg.
    Measured at room temperature.


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