Prediction of concentration immediately dangerous to life or health of benzene and its derivatives based on quantitative structure-activity relationship / 环境与职业医学

Background With the increasing exposure to hazardous chemicals in the workplace and frequency of occupational injuries and occupational safety accidents, the acquisition of occupational exposure limits of hazardous chemicals is imminent. Objective To obtain more unknown immediately dangerous to life or health (IDLH) concentrations of hazardous chemicals in the workplace by exploring the application of quantitative structure-activity relationship (QSAR) prediction method to IDLH concentrations, and to provide a theoretical basis and technical support for the assessment and prevention of occupational injuries. Methods QSAR was used to correlate the IDLH values of 50 benzene and its derivatives with the molecular structures of target compounds. Firstly, affinity propagation algorithm was applied to cluster sample sets. Secondly, Dragon 2.1 software was used to calculate and pre-screen 537 molecular descriptors. Thirdly, the genetic algorithm was used to select six characteristic molecular descriptors as dependent variables and to construct a multiple linear regression model (MLR) and two nonlinear models using support vector machine (SVM) and artificial neural network (ANN) respectively. Finally, model performance was evaluated by internal and external validation and Williams diagram was drawn to determine the scopes of selected models. Results The ANN model results showed that \begin{document}$ {R}_{\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{i}\mathrm{n}}

Study on Varieties and Contents of Related Substances in Cefonicid Sodium by HPLC and MS / 中国药师

Objective:To study the varieties and contents of related substances in cefalotin sodium by HPLC and MS. Methods:The quantitative determination of impurity spectra was carried out using self-contrast method, and UPLC-MS was used to preliminarily i-dentify the variety of impurities. Results:Through the study on the ascription and content of the related substances, there were 6 sub-stances existing in cefalotin sodium, and through the structure analysis, the 6 substances showed antibiotic action and toxicity. Conclu-sion:The method is simple, stable and repeatable, which can be used for the determination of cefalothin sodium and related sub-stances.