[Study on endpoint determination and process analysis of tablet coating based on near infrared spectroscopy].

To conduct endpoint determination of tablet coating and analyze coating process by near-infrared spectroscopy(NIRS). Firstly, the layered k-fold cross validation was used to discuss the optimal combination of spectral interval and preprocessing method, and the optimal result was used as the modeling condition. Secondly, in above condition, the qualitative model was proposed based on the throught of principal component analysis(PCA) and confidence interval, this model and the conformity test model were established respectively in this study, and the discrimination performance of coating eligibility was calculated. Then, the internal cross validation was used to obtain the coating end-point conforming rate as the threshold for determining the endpoint of tablet coating. Finally, the results of predicted conforming rate and discrimination parameters for the test samples of different batches were calculated with the above models, which were then further used for end-point detection and process analysis. As compared with the conformity test, this method proposed in this study was more accurate and stable in determining the coating conformity, and the coating endpoint can be accurately determined when 95% of the eligibility rate was used as the discriminant threshold. Meanwhile, in the process analysis, the change trend of the process parameters(model discrimination parameters, prediction conforming rate) was basically consistent with that in the conformity test. The results indicate that the method proposed in this study has a good and stable performance, which can be used to determine the endpoint of coating and analyze the process. It is of great significance to reduce the difference between batches and improve the product consistency. Meanwhile, this research method also lays a foundation for the future researches by online near infrared measurements.

[Correlation between water state and texture during moistening of Paeoniae Radix Alba by LF-NMR/MRI].

The changes of active ingredients content, moisture status and texture characteristics during the moistening of Paeoniae Radix Alba were studied by low-field NMR and imaging(LF-NMR/MRI) and texture analyzer, so as to analyze the correlation between LF-NMR parameters, texture characteristics and active ingredient content of Paeoniae Radix Alba during the moistening at diffe-rent times. The results showed that MRI technology could directly, vividly and accurately characterize the degree of moistening and the process of water migration, and the degree of moistening was consistent with the judgment results of traditional experience. The characteristics of moisture migration and moisture phase state in the moistening process of Paeoniae Radix Alba were that the total water content increased and existed in the form of free water, with an increased moisture mobility. In the case of dampening, the total water content did not increase, but the more watery part of the medicinal material was distributed to the less watery part, with a reduced fluidity. Finally, the medicinal materials were moistened, which can be mutually verified with the MRI results. The free water content and the total water content of Paeoniae Radix Alba had extremely negative correlations with hardness, surface toughness, internal toughness, Paeoniflorin and albiflorin contents(P<0.01). It showed that the use of LF-NMR/MRI and texture analyzer could better characterize the moistening process. It provides data characterization for the scientific connotation of "less soaking and more moisturizing, and the drug is completely saturated with water", and the traditional experience of "observing the water head". The feasible and objective evaluation method was helpful to optimize the softening process parameters, scientifically standardize the operating specifications, define the scienti-fic connotation of traditional Chinese medicine softening, and promote the inheritance and innovation of traditional Chinese medicine processing.