title: Characterization of monoclinic crystals in tablets by pattern-fitting procedure using X-ray powder diffraction data.
abstract: The purpose of this study is to characterize the monoclinic crystals in tablets by using X-ray powder diffraction data and to evaluate the deformation feature of crystals during compression. The monoclinic crystals of acetaminophen and benzoic acid were used as the samples. The observed X-ray diffraction intensities were fitted to the analytic expression, and the fitting parameters, such as the lattice parameters, the peak-width parameters, the preferred orientation parameter and peak asymmetric parameter were optimized by a non-linear least-squares procedure. The Gauss and March distribution functions were used to correct the preferred orientation of crystallites in the tablet. The March function performed better in correcting the modification of diffraction intensity by preferred orientation of crystallites, suggesting that the crystallites in the tablets had fiber texture with axial orientation. Although a broadening of diffraction peaks was observed in acetaminophen tablets with an increase of compression pressure, little broadening was observed in the benzoic tablets. These results suggest that "acetaminophen is a material consolidating by fragmentation of crystalline particles and benzoic acid is a material consolidating by plastic deformation then occurred rearrangement of molecules during compression". A pattern-fitting procedure is the superior method for characterizing the crystalline drugs of monoclinic crystals in the tablets, as well as orthorhombic isoniazid and mannitol crystals reported in the previous paper.
authors.affiliation: School of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan. yamamura@phar.toho-u.ac.jp
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yamamura
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Momose
mesh_terms: D000082:Acetaminophen / Q000737:chemistry*; D000465:Algorithms; D019817:Benzoic Acid / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D019245:Compressive Strength; D003460:Crystallization; D010363:Pattern Recognition, Automated; D033362:Powder Diffraction; D012985:Software Design; D016008:Statistical Distributions; D013607:Tablets; D014961:X-Ray Diffraction
chemical_list: D013607:Tablets; D000082:Acetaminophen; D019817:Benzoic Acid