ABSTRACT
The preparation of polymorphic forms of rivaroxaban was carried out using a recrystallization method based on that for crystal form-Ⅰ. Preparation methods were developed for two crystal forms-Ⅱ (medicinal crystal form) and five crystal forms-Ⅳ and the crystals were then characterized. The crystalline form was identified by applying modern analytical means including X-ray powder diffraction (PXRD), differential scanning calorimetry (DSC), element analysis (EA), mass spectrometry (MS), and infrared spectrum (IR), and the morphology of different crystal forms was observed by scanning electron microscopy (SEM). The results show that the PXRD and DSC characteristics of prepared crystal forms-II and IV are consistent with those described in patents at home and abroad, and the test results with EA, MS and IR are in accordance with the chemical structure of rivaroxaban. The crystal form-I is lamellar, the crystal form-II is linear and crystalline form-IV is striped as determined by SEM. In summary, the methods for preparing crystal form-II and form-IV are reliable, the required reagents are easily available, the experimental conditions are easy to implement and the preparation process is simple. Our study provides a new reference for the production and application of rivaroxaban.
ABSTRACT
In this paper, three methods, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray powder diffraction (PXRD), were used to characterize the structure of Palbociclib. The form-B crystal mixed in with form-A crystal, the effective form of Palbociclib, was quantitated by the single peak method (peak area method and peak height method) using X-ray powder diffraction. While the qualitative identification by DSC was not clear, SEM and PXRD quickly and effectively identified two types of crystal. The standard curve equations established by the peak area method and the peak height method are: y = 0.842 75x - 0.001 21 and y = 0.909 64x - 0.002 32. This suggests that the linear relationship of peak area method is better than that of peak height method (R2 = 0.986 17 and R2 = 0.985 83). The sensitivity of the peak area method (LOD = 1.17%, LOQ = 3.92%) are higher than the peak height method (LOD = 1.19%, LOQ = 3.97%). The methods from this study can be used to identify and quantify palbociclib form-A and form-B crystal rapidly.
ABSTRACT
Objective: To determine the content of crystal type α in glycine by X-ray power diffraction technique to provide evi-dence for the polymorphic research. Methods: A calibration curve was established by using the characteristic peak ratio of glycine form α at 2θ=19. 1° to form γ at 2θ=25. 4° as the quantitative parameter to determine the content of crystal type α. Results: The charac-terization figures of form α and form γ were obtained. The linear range of form α was 1%-99% (r=0. 996 7), and the average recov-ery was 102. 8% with the RSD of 4. 0% (n=9). Conclusion: X-ray powder diffraction method is a feasible analytical method for the quantitative determination of form α and form γ of glycine with simple,sensitive and accurate properties.
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The aim of this study was to establish the methods to identify crystal form of dasatinib in tablets.X-ray powder diffraction(XRPD)and solid-state nuclear magnetic resonance(ssNMR)were used to analyze the crystal form of dasatinib in Sprycel? tablets and Yinishu? tablets.The results showed that monohydrate and anhydrate were identified in Sprycel? and Yinishu? tablets respectively;with no detectable anhydrate in Sprycel? tablets and no detectable monohydrate in Yinishu? tablets.The results of XRPD and ssNMR were consistent;and could be both applied in the crystal form identification of dasatinib in tablets.
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Objective: To explore a method to improving the in vitro dissolution of tanshinone IIA spray drying powder and to study its pharmceutical properties. Methods: Tanshinone IIA was processed with spray drying method and analyzed by determination of the specific surface area (BET), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray powder diffraction (XRPD). And in vitro dissolution and drug stability were also investigated. Results: The BET results showed that tanshinone IIA powder after spray drying had narrow particle size distribution range and large specific surface area; XRD and DSC analyses showed that most drug was transformed into amorphous form. The in vitro dissolution achieved 85.2% within 8 h. Accelerating experiment showed that the in vitro dissolution of tanshinone IIA decreased by approximately 21% stored for 6 months. Conclusion: The drug dissolution is improved by spray-drying method. It provides a reference for the research and development of poorly soluble pharmaceutical preparations for oral administration.
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Objective To investigate the influences of polyethylene glycol on the solubility and in vitro dissolution of m-nisoldipine,which could provide guidance for chosing formulations of m-nisoldipine. Methods Solid dispersions of m-nisoldipine were prepared by solvent-melting method with polyethylene glycol6000 matrix. DSC and XRD spectroscopy were applied to identify the solid dispersions. The solubility and in vitro dissolution were detected by UV spectroscopy. Results The DSC and XRD map were different from the crude drug and their physical mixtures. The dissolution rates(13,15,17) were faster(35. 31%,38. 71%,41. 48%) than that of the crude drug(26. 80%),and the dissolution rates of the solid dispersions in the same ratio were higher than the physical mixtures. Conclusion DSC analysis indicated that eutectic compounds were produced by the m-nisoldipine and polyethylene glycol,in which polyethylene glycol6000 acts as a carrier. The solubility and in vitro dissolution of m-nisoldipine can be increased.
ABSTRACT
Objective:To develop nano-TiO_2 ceramic-coated orthodontic brackets, and to study the surface characters of ceramic film. Methods:TiO_2 nanoparticles were synthesized by the Gel-Sol method. Electron beam physical vapor deposition(e-beam PVD)technology was used to deposit the nano-TiO_2 ceramic film on the surface of the orthodontic brackets, which were manufactured by the Xinya factory, Hangzhou.The surface properties of the nano-TiO_2 ceramic film were observed with scanning electron microscopy(SEM),transmission electron microscopy(TEM) and X ray power diffraction(XRD).Results:The synthesized TiO_2 particles were uniform with the diameter of (6?2) nm. The TiO_2 ceramic film on the orthodontic brackets was 5~8 ?m in thickness, with smooth surface and anatase stratiform structure.Conclusions:The nano- TiO_2 ceramic film has good surface properties and actinochemistry characters without any influence on the slot size.