The crystal structure of altrenogest has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Altrenogest crystallizes in space group P212121 (#19) with a = 7.286 916(16), b = 10.580 333(19), c = 22.266 08(7) Å, V = 1716.671(6) Å3, and Z = 4 at 295 K. Thermal expansion between 113 and 295 K is anisotropic. An O–H⋯O hydrogen bond links the molecules into chains along the c-axis. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

The crystal structure of aminopentamide hydrogen sulfate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Aminopentamide hydrogen sulfate crystallizes in space group P21/c (#14) with a = 17.62255(14), b = 6.35534(4), c = 17.82499(10) Å, β = 96.4005(6)°, V = 1983.906(14) Å3, and Z = 4. The structure consists of layers parallel to the bc-plane with hydrogen sulfate anions at the core and aminopentamide cations on the outside. There is a strong charge-assisted O49–H53⋯O52 hydrogen bond between the hydrogen sulfate anions. This hydrogen bond links the anions in a chain parallel to the b-axis. The cation forms a discrete N–H⋯O hydrogen bond to the anion. The amide group also forms two weaker discrete hydrogen bonds to the anion. The three N–H⋯O hydrogen bonds link the cations and anions into columns parallel to the b-axis. This commercial material from USP contained an unidentified impurity, the powder pattern of which could be indexed on a monoclinic unit cell. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

Numerical estimators of differential entropy and mutual information can be slow to converge as sample size increases. The offset Kozachenko–Leonenko (KLo) method described here implements an offset version of the Kozachenko–Leonenko estimator that can markedly improve convergence. Its use is illustrated in applications to the comparison of trivariate data from successive scene color images and the comparison of univariate data from stereophonic music tracks. Publicly available code for KLo estimation of both differential entropy and mutual information is provided for R, Python, and MATLAB computing environments at https://github.com/imarinfr/klo.

The crystal structure of anhydrous alfuzosin hydrochloride has been solved and refined using laboratory X-ray powder diffraction data and optimized using density functional theory techniques. Anhydrous alfuzosin hydrochloride crystallizes in space group P-1 with a = 9.3214(16), b = 9.3997(29), c = 12.6172(64) Å, α = 107.993(11), β = 100.386(9), γ = 90.229(6)°, V = 1032.1(10) Å3, and Z = 2 at ambient conditions. Thermal expansion is anisotropic, being 8× larger in the c-direction than in the other two. The crystal structure is characterized by a stack of planar fused rings along the b-axis, and layers of the more-corrugated portion of the molecule parallel to the ab-plane. There are two strong N–H⋯Cl hydrogen bonds, as well as seven C-H⋯Cl hydrogen bonds. The powder patterns have been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

This paper aims to explore the influence of solvent effects on the crystal habit of venlafaxine hydrochloride using the modified attachment energy (MAE) model by molecular dynamics (MD) simulation. Solvent effects were investigated based on the different morphologies of venlafaxine hydrochloride acquired by simulation and experimental technology from the solvents of isopropanol, dimethyl sulfoxide, and acetonitrile. Firstly, morphologically dominant crystal faces were obtained through the prediction of crystal habit in vacuum by the attachment energy (AE) model. Subsequently, the MAEs were calculated by the MD simulation to modify the crystal shapes in a real solvent environment, and the simulation results were in agreement with the experimental ones. Meanwhile, in order to have a better understanding of the solvent effects, the surface structure was introduced to analyze the solvent adsorption behaviors. The results show that the crystal habits of venlafaxine hydrochloride are affected by the combination of the AE and surface structures. Finally, the flowability of the obtained crystal powders from different solvents was investigated by measurement and analysis of the angle of repose and compressibility. The above results verify that the physical properties are closely related to the morphologies of the crystals.

X-ray powder diffraction data, unit-cell parameters, and space group for the topiroxostat form II, C13H8N6, are reported [a = 7.344(9) Å, b = 12.946(7) Å, c = 12.133(5) Å, β = 96.99(3)°, V = 1145.2(4) Å3, Z = 4, and space group P21/c]. The topiroxostat monohydrate, C13H8N6·H2O, crystallized in a triclinic system and unit-cell parameters are also reported [a = 7.422(9) Å, b = 8.552(1) Å, c = 11.193(5) Å, α = 74.85(1)°, β = 81.17(1)°, γ = 66.29(1)°, V = 627.0(6) Å3, Z = 2, and space group P-1]. In each case, all measured lines were indexed and are consistent with the corresponding space group. The single-crystal data of two solid-state forms of topiroxostat are also reported, respectively [a = 7.346(2) Å, b = 12.955(2) Å, c = 12.130(7) Å, β = 96.91(6)°, V = 1146.1(3) Å3, Z = 4, and space group P21/c] and [a = 7.418(6) Å, b = 8.532(8) Å, c = 11.183(9) Å, α = 74.807(1) °, β = 81.13(1)°, γ = 66.32(1) °, V = 624.7(6) Å3, Z = 2, and space group P-1]. The experimental powder diffraction pattern has been well matched with the simulated pattern derived from the single-crystal data.