![]() XRPD data depicted as Debye-Scherrer rings were also obtained from virus proteins and specifically from precipitated tobacco mosaic virus proteins. The crystalline properties of individual polymorphs and their direct correlation with a drug’s absorption, distribution, metabolism and excretion (ADME) characteristics can lead to the production of more efficient, or macromolecular, formulations with alternative methods of delivery such as sustained-release or inhaled compounds. XRPD is extensively used for the identification of specific components when examining intermixtures of inorganics or small organics, while its applicability is steadily increasing in the context of characterizing new pharmaceutically important phases of biological macromolecules which, in combination with the crystalline nature of the corresponding compound, may display advantageous properties as increased solubility and prolonged release of the beneficial agent. A pharmaceutical composition may consist of more than one component, each of which is an active pharmaceutical ingredient. Screening of crystalline polymorphism is a very important step in the structural characterization of molecules of pharmaceutical interest as different crystalline polymorphs are often associated with modified physicochemical properties and/or biological activity. Owing to the simplicity of the XRPD data collection process and the sensitivity of the method, since each polymorph reveals a unique pattern, the technique has become a robust tool for thorough examination of a wide range of microcrystalline precipitates. These studies further manifest the efficiency of protein XRPD for quick and accurate preliminary structural characterization. This review congregates recent studies in the field of drug formulation and delivery processes, as well as in polymorph identification and the effect of ligands and environmental conditions upon crystal characteristics. An overview of the XRPD applications and recent improvements related to the study of challenging macromolecules and peptides toward structure-based drug design is discussed. Owing to recent methodological advances, this method is now considered a respectable tool for identifying macromolecular phase transitions, quantitative analysis, and determining structural modifications of samples ranging from small organics to full-length proteins. Among other methods, X-ray powder diffraction (XRPD) has proved its applicability and efficiency in numerous studies of different materials. #POWDER DIFFRACTION FULL#There is hardly any field of crystallography where the Rietveld, or full pattern method has not been tried with quantitative phase analysis the most important recent application.Providing fundamental information on intra/intermolecular interactions and physicochemical properties, the three-dimensional structural characterization of biological macromolecules is of extreme importance towards understanding their mechanism of action. In the last decade the interest has dramatically improved. Powder diffraction today is used in X-ray and neutron diffraction, where it is a powerful method in neutron diffraction for the determination of magnetic structures. With the development of ever growing computer power profile fitting and pattern decomposition allowed to extract individual intensities from overlapping diffraction peaks opening the way to many other applications, especially to ab initio structure determination. In the late 60s the inherent potential of powder diffraction for crystallographic problems was realized and scientists developed methods for using powder diffraction data at first only for the refinement of crystal structures. X-ray powder diffraction is best known for phase analysis (Hanawalt files) dating back to the 30s. Crystal structure analysis from powder diffraction data has attracted considerable and ever growing interest in the last decades. ![]()
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