Flupirtine maleate, a pharmaceutical compound for treating psychotic disease in clinics, has seven polymorphs. Form A, with better crystal stability and bioavailability, has been widely used as the pharmaceutical crys...Flupirtine maleate, a pharmaceutical compound for treating psychotic disease in clinics, has seven polymorphs. Form A, with better crystal stability and bioavailability, has been widely used as the pharmaceutical crystal form. Unfortunately, it is usually found in a polymorphic mixture with form B. In this study, pure crystal forms of A and B were prepared and characterized by X-ray powder diffraction （XRPD）, Fourier transform infrared spectroscopy （FT-IR） and thermal analysis. An XRPD-based method for the quantitative determination of the amount of the flupirtine maleate polymorphs form A and form B was also established through a systematic optimization of instrumental parameters. The results of the analytical methodology validation showed that the XPRD method had a broad quantitative range of 0- 100% （w/w）, good linear relationship, with R2= 0.999, excellent repeatability and precision and low limits of detection （LoD） of 0.15% （w/w） and quantification （LoQ） of 0.5% （w/w）. The results also showed that the single-peak method was not as good as the whole pattern in reducing the influence of the preferred orientation, but this can be compensated for by a systematic optimization of instrumental parameters and validating the analytical methodology to reduce errors and obtain a good, repeatable, sensitive, and accurate method. This XRPD method can be used to analyze mixtures of flupirtine maleate polymorphs （forms A and B） quantitatively and control the quality of the bulk drug.展开更多
The kinetic characteristics of apricots during orientation transmission were studied to provide a basis for improving the structure of the transmission device.Previous studies have generally focused on the development...The kinetic characteristics of apricots during orientation transmission were studied to provide a basis for improving the structure of the transmission device.Previous studies have generally focused on the development of orientation devices,but few studies have been conducted to analyze the mechanisms of orientation.In order to study the attitude control in the orientation mechanisms,an orthogonal combination test was performed and a rigid kinetic model for a monosymmetric apricot was developed based on Euler’s kinetic equations with the modified Rodrigue parameters(MRPs).Kinetic simulation and analysis based upon the attitude control law were conducted and an attitude control simulation platform was created.The simulation results showed that the orientation transmission system for monosymmetric apricots was globally convergent and tended to stable.The experimental torques also affected the orientation success rates.The calculated average experimental torque value(0.164 N·m)was consistent with the maximum control torque value(0.16478 N·m)when the system was in a stable state in Simulink.The consistency between the simulation result and the calculated control torque validates the correctness of the designed control torques.展开更多
基金supported by the Major Program of Ministry of Science and Technology of China(No:2015ZX09J15104-003002)
文摘Flupirtine maleate, a pharmaceutical compound for treating psychotic disease in clinics, has seven polymorphs. Form A, with better crystal stability and bioavailability, has been widely used as the pharmaceutical crystal form. Unfortunately, it is usually found in a polymorphic mixture with form B. In this study, pure crystal forms of A and B were prepared and characterized by X-ray powder diffraction （XRPD）, Fourier transform infrared spectroscopy （FT-IR） and thermal analysis. An XRPD-based method for the quantitative determination of the amount of the flupirtine maleate polymorphs form A and form B was also established through a systematic optimization of instrumental parameters. The results of the analytical methodology validation showed that the XPRD method had a broad quantitative range of 0- 100% （w/w）, good linear relationship, with R2= 0.999, excellent repeatability and precision and low limits of detection （LoD） of 0.15% （w/w） and quantification （LoQ） of 0.5% （w/w）. The results also showed that the single-peak method was not as good as the whole pattern in reducing the influence of the preferred orientation, but this can be compensated for by a systematic optimization of instrumental parameters and validating the analytical methodology to reduce errors and obtain a good, repeatable, sensitive, and accurate method. This XRPD method can be used to analyze mixtures of flupirtine maleate polymorphs （forms A and B） quantitatively and control the quality of the bulk drug.
基金the financial support of the National Natural Science Foundation Program of China(Grant No.51165042).
文摘The kinetic characteristics of apricots during orientation transmission were studied to provide a basis for improving the structure of the transmission device.Previous studies have generally focused on the development of orientation devices,but few studies have been conducted to analyze the mechanisms of orientation.In order to study the attitude control in the orientation mechanisms,an orthogonal combination test was performed and a rigid kinetic model for a monosymmetric apricot was developed based on Euler’s kinetic equations with the modified Rodrigue parameters(MRPs).Kinetic simulation and analysis based upon the attitude control law were conducted and an attitude control simulation platform was created.The simulation results showed that the orientation transmission system for monosymmetric apricots was globally convergent and tended to stable.The experimental torques also affected the orientation success rates.The calculated average experimental torque value(0.164 N·m)was consistent with the maximum control torque value(0.16478 N·m)when the system was in a stable state in Simulink.The consistency between the simulation result and the calculated control torque validates the correctness of the designed control torques.
