ABSTRACT
Near-infrared spectroscopy (NIRS) combined with chemometrics can achieve rapid detection in process analysis. After variable selection, the redundant information is effectively removed and the characteristic variables related to the response values are selected. Compared with global model, the complexity is significantly reduced and the prediction accuracy is also improved. In this study, near-infrared spectroscopy analysis combined with different variable selection methods was applied to achieve the rapid detection of baicalin in the extraction process of Scutellaria baicalensis. Data sets were divided based on sample set portioning based on joint x-y distance (SPXY) method. Competitive adaptive weighted resampling method (CARS), random frog (RF) and successive projections algorithm (SPA) were applied to variable selection. Partial least squares (PLS) models were constructed based on above three methods, and the prediction results were compared. After CARS, RF and SPA method, 92, 10 and 17 variables were screened out respectively. According to the performance of the models, CARS method is found to be more effective and suitable than RF and SPA. Furthermore, the characteristic variables selected by CARS method have a better correspondence with the chemical structure of baicalin. The root mean square error (RMSEC) of the calibration set and the root mean square error (RMSEP) of the prediction set are 0.528 2 and 0.720 2 respectively. Compared with the global PLS model, the correlation coefficient of the calibration set (Rc) is increased to 0.979 9 from 0.917 0, and the relative standard errors of prediction (RSEP) is reduced to 5.59% from 10.58%.
ABSTRACT
<p><b>OBJECTIVE</b>To understand the particle settling characteristics of alcohol precipitation mixture of Paeoniae Radix rubra extract and establish models of the sedimentation rate.</p><p><b>METHODS</b>Focusing on the particle settling characteristics such as particle settling curve, particle settling velocity (PSV), particle volume index (PVI), the particle settling process of alcohol precipitation was investigated. The effect of three key process factors on the settling process was discussed and mathematical models for describing the particle settling velocity were developed.</p><p><b>RESULTS</b>Controlling of higher final alcohol concentration, higher density of Paeoniae Radix rubra extract, or lower initial alcohol concentration, was conducive to settlement of alcohol precipitation particles. In the constant speed phase, an empirical calculation formula of v(0) was established, with both the variables PSV and PVI (v(0)=-0.236PSV+0.022PVI+7.521). Another developed model was applied to predict the settling velocity in decelerated phase and the simulation was very good [v=k(1-n(1)X)(4)exp(-n(2)X)/X].</p><p><b>CONCLUSION</b>The results of this work will contribute to a better control and optimization of alcohol precipitation process, and help to implementation of accuracy control in the manufacture of botanical medicines.</p>
Subject(s)
Drugs, Chinese Herbal , Models, Theoretical , Paeonia , ChemistryABSTRACT
<p><b>OBJECTIVE</b>To investigate the optimal alcohol precipitation parameters for extract of Carthamus tinctorius.</p><p><b>METHODS</b>The effects of different factors on the transfer rate of hydroxy safflower yellow A (HSYA) was studied via single factor experiments, including the final alcohol concentration of the liquor, the speed of stirring, the initial density of the extract, the temperature and the pH of the liquor. Based on the results of single factor experiments, the final alcohol concentration of the liquor, the speed of stirring, the initial density of the extract and the pH of the liquor were studied by an orthogonal test and a multiple guidelines grading method, and the transfer rate of HSYA, the yield and the purity of extract in the supernatant were used as comprehensive evaluation index.</p><p><b>RESULT</b>The optimal alcohol precipitation process of Carthamus tinctorius extract was as follows: the final alcohol concentration of the liquor 50%, the speed of stirring 500 r/min, the initial density of the extract 1.15 g/ml and the pH of the liquor 5.0.</p><p><b>CONCLUSION</b>The proposed alcohol precipitation process is convenient and steady with high transfer rate of HSYA, high yield and purity of extract in the supernatant.</p>