An improved prediction model of morphological modifications of organic crystals induced by additives

Abstract

Additives have a great effect on the crystal morphology of organic compounds. The molecular modeling techniques were applied to predict the morphological modifications induced by additives. Besides molecular modeling software additionally some simulation approaches are needed. The build-in and the surface docking approaches were applied to some host-additive-systems. It will be presented here that the suitability of these two approaches depends on the degree of anisotropy of the intermolecular bonding of the host substance. A procedure on how to choose an appropriate prediction approach for the individual crystal systems on investigation is suggested.

Crystal structure of aluminum sulfate hexadecahydrate and its morphology

“…Second, the morphologically important surfaces (h k l) obtained through AE simulation were reconstructed as periodic superstructures of more than 25Å 2 × 25Å 2 with 3 d hkl thickness. The solvent layers (ρ = 1 g/cm 3 ) filled with 200 randomly distributed water molecules were built using "Amorphous Cell" tool, and their sizes were selected to match with the superstructures of the morphologically important surfaces. The solvent layers were geometrically optimized, and their molecular dynamics were assessed using the NHL thermostat (NVT ensemble, 100 ps with time step 0.1 fs at 298 K).…”

“…Computer simulations have been widely used to predict the morphology of crystals in vacuum and real systems [3][4][5]. The most widely used prediction models are Bravais-Friedel-Donnay-Harker (BFDH) [3] and attachment energy (AE) [5,6].…”

“…The most widely used prediction models are Bravais-Friedel-Donnay-Harker (BFDH) [3] and attachment energy (AE) [5,6]. BFDH model uses the crystal lattice and symmetry to generate possible growth faces and determine their relative growth rates without considering the energetics of the system.…”

Solvent Effect on Crystal Structure of Tetracycline Hydrochloride

“…Finally, the slowest growing face becomes the most important one with the biggest area. E hkl int can be calculated by setting up a solvent-crystal layer through MS [16][17][18][19][20] according to Eq. (1).…”

The influence of supersaturation on crystal morphology – experimental and theoretical study

“…Cerius 2 -offers the possibility to predict the crystal morphology, it does not consider the influence of the external process conditions. In order to predict the crystal morphology in the presence of additives two additional simulation methods, the build-in [1,2] and the surface docking approach [3,4], have been developed as shown in figure 1. However, neither of these two approaches takes into account the influence of supersaturation on crystal morphology, which does play an important role in addition to additives.…”