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Mechanical treatment with addition of some liquid, crystallization from solutions, and heating of the mixture components preliminary subjected to mechanical treatment were the methods used for the preparation of the co-crystals of 4-hydroxy-2-methyl- N-(5-methylthiazol-2-yl)-2 H-1,2-benzothiazin-3-carboxamide 1,1-dioxide (meloxicam) with carboxylic acids. It was shown that preliminary mechanical treatment plays significant role for the synthesis, whereas the addition of small amounts of solvents accelerates the process. The co-crystals were obtained for 17 mixtures of meloxicam-carboxylic acid. The use of the co-crystals of meloxicam in the compositions of improved pharmaceutical forms was found promising, which was attributable to the fact that the dissolution rate and the solubility of the co-crystals of meloxicam with the carboxylic acids under study are higher than those for meloxicam itself. [ABSTRACT FROM AUTHOR]

The crystal structure of the 1:1 ethanol betulin solvate, a widely spread natural compound, is determined. The betulin solvate crystallizes in orthorhombic symmetry in the P222 space group, Z= 4. The unit cell parameters are as follows: a = 7.0159(1) Å, b = 12.4425(2) Å, c = 33.7500(5) Å; V = 2946.22(8) Å. Betulin molecules are hydrogen bonded to each other and ethanol molecules, as a result of which the layers are distinguished in the structure, which are perpendicular to the crystallographic direction. Inside the layer, all molecules are hydrogen bonded, while the layers are linked by van der Waals interactions. [ABSTRACT FROM AUTHOR]