目的 考察X射线衍射法(PXRD)检测不同粒度药用晶体时的衍射峰峰强度、峰个数及其强弱顺序变化,评价在不同药典指导原则下该检测结果对药物晶型判定的影响。方法 以无机和有机药用晶体作为研究对象,筛分或研磨获得同一晶型的不同粒径样品用以PXRD检测,对比不同样品的衍射峰数量、峰强、峰位置以及峰强弱顺序的变化情况。结果 由于晶粒在检测时的择优取向,同一晶型的不同粒径的样品在PXRD检测中会表现为PXRD衍射谱图中衍射峰数量、衍射峰相对强度以及衍射峰强弱顺序的变化。结论 同一检测结果,根据2015年版《中国药典》和美国等国家药典的相关指导原则来鉴别晶型,会得出不同的结论。现将其提出讨论,以期进一步完善晶型鉴定的标准,提高晶型鉴定的水平,从而进一步确保晶型鉴定方法的准确性,为建立专业的晶型鉴定方法提供参考意见和依据。

OBJECTIVE To investigate the impacts of particle size and preferred orientation on relative peak intensity, number of peaks and order of peak intensity in powder X-ray diffraction (PXRD) analysis of organic and inorganic pharmaceutical crystalline materials and evaluate the phase identification methods in various pharmaceutical compendiums.METHODS The PXRD patterns of organic and inorganic materials with different particle sizes obtained by sieving or grinding were acquired and the number of diffraction peaks, peak position and intensity of diffraction peaks were compared across different samples. RESULTS Due to preferred orientation effects, the diffraction patterns of samples with different particle sizes were apparently different, including the number of peaks, relative peak intensity and the order of the peak intensity. CONCLUSION Scientists may get different CONCLUSION s from the RESULTS of same tests performed according to the related guiding principles of current Chinese Pharmacopeia and USP39, EP8.0, JP16 ⅩⅥ pharmacopoeia for identifying the crystalline forms.The phase identification by PXRD method in current Chinese Pharmacopeia neglects the effects of preferred orientation on diffraction peaks and relative peak intensity. This guideline needs to be updated to better reflect the scientific observation in industry and align with other well accepted compendiums such as USP, EP and JP.