No abstract

Near-infrared spectroscopy has been widely used in qualitative and quantitative analysis and online monitoring in the production process of traditional Chinese medicines. The aim was to establish a fast determination model of zinc oxide (ZnO) content in calcined calamine and to explore methods through judging the end point of calamine calcination. Eight batches of calamine samples sourced from hydrozincite with different sizes and textures were calcined at different temperatures. During the calcination process, ZnO contents, X-ray diffraction (XRD) patterns, and near-infrared spectra of the samples were used to analyze their changes rules. The model of determining ZnO content of calcined calamine was established to use near-infrared spectroscopy based on the partial least squares (PLS) regression algorithm. In addition, this paper summarized the change rules of calamine in calcination according to XRD patterns, using the “K value” quantitative method to define the characteristic T value. When the T value was equal to 1.00 (100%), that is to say, the calamine sample was completely calcined. Then, matching the near-infrared spectroscopy data with the T value and establishing the T value analysis model using the PLS algorithm were performed. Through cross and independent validation and evaluation, it was proved that the two models were very effective and had strong predictive abilities. Finally, the purpose of the online monitoring of the calcination process and controlling the quality of the calcined calamine was achieved.

IR and Raman spectra of three kinds of mineral drug montmorillonite powders (brands Biqi, Smecta general, Smecta strawberry flavour) commercially available for children are obtained to tell the true from the false through checking the spectral information of the active ingredient (montmorillonite) and pharmaceutical excipients (glucose, saccharin sodium, vanillin and strawberry essence). It is found that net contents of the active ingredient in all three drugs maybe really high and even the cheapest brand is also with a high quality. From this study one can see that the IR spectroscopic method is more suitable for this kind of drug identification than the Raman one using the present Raman spectroscope because strong fluorescent signals excited by lasers on the pharmaceutical excipients can generally cover up the fingerprint signals of the active ingredient.

Fourier transform (FT) infrared (IR) and Raman spectra of powders in the Biqi capsule, a commercially available national-level combination medicine, are measured to check the information on the most important active ingredient strychnine, which is in fact a highly toxic drug. Referring to the published FTIR absorption and FT Raman spectral data, from our ones we have found that the active ingredient - strychnine in our purchased Biqi capsule really exists and its net content is really not so high and therefore may not cause a serious harm to patients if an approved dosage is eaten. From this study one can see that the IR spectroscopic method is more suitable for this kind of drug identification than the Raman one using the Raman spectroscope in this experiment because strong fluorescent signals excited by lasers on the pharmaceutical excipients and other subordinate active ingredients generally cover up the fingerprint signals of the active ingredient in the drug.